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How to Reduce the Cost of Feeding Tilapia

Mary is a tilapia farmer in Brazil. Through her articles, she shares insights and tips to make your farm more profitable.

This a picture of one of our lakes full of fish. In this photo, you will see several cages. The 2m X 2m can hold up to 600 adult fish, and the 3m x 2m can take up to 900 fish. These are fed by rowboat.

This a picture of one of our lakes full of fish. In this photo, you will see several cages. The 2m X 2m can hold up to 600 adult fish, and the 3m x 2m can take up to 900 fish. These are fed by rowboat.

Buying and Raising Tilapia

It's easy to look at the rearing of tilapia and think that it's easy money. If you buy young fish, they are inexpensive. In fact, here in Brazil, they are sometimes free to encourage farmers to raise their own food. The larger they are, the more costly. We buy fish that are two months old and weigh about 50 grams. This ensures they will be unable to swim out of the cages that we use. These cost more but have decreased the growing time by two months.

The chart below will show you just how much food is necessary to feed 1,000 fish.


Tilapia Feeding Chart

Size of feed pelletsWeight of fish (grams)Age of tilapia (weeks)Number of feeds per dayDaily amount per 1000 fish

Powder

0.5-2

1

12

225g

Powder

2-3.5

2

10

440g

Powder

3.5-5

3

10

680g

1.7mm

5-7

4

9

600g

1.7mm

7-12

5

8

760g

1.7mm

12-20

6

7

1.1kgs

2-4 mm

20-30

7

5

1.5kgs

2-4 mm

30-50

8

5

2.0kgs

2-4 mm

50-75

9

5

3.1kgs

2-4 mm

75-100

10

5

4.4kgs

4-6mm

100-115

11

4

4.8kgs

4-6mm

115-140

12

4

5.7kgs

4-6mm

140-170

13

4

6.2kgs

4-6mm

170-200

14

4

7.4 kgs

6-8mm

200-240

15

3

8.8 kgs

6-8mm

240-280

16

3

9.1kgs

6-8mm

280-325

17

3

10.6kgs

6-8mm

325-370

18

3

12.2kgs

6-8mm

370-420

19

3

11.9kgs

6-8mm

420-475

20

3

13.4kgs

6-8mm

475-535

21

3

12.6kgs

6-8mm

535-595

22

3

11.3kgs

6-8mm

595-660

23

3

12.6kgs

6-8mm

660-725

24

3

13.9kgs

6-8mm

725-795

25

3

11.4kgs

6-8mm

795-870

26

3

12.5kgs

6-8mm

870-945

27

3

13.6kgs

6-8mm

945-1025

28

3

14.8kgs

6-8mm

1025-1110

29

3

16kgs

6-8mm

1110-1200

30

3

11.6kgs

 

 

 

 

 

At What Size Can You Sell Tilapia?

You can see that the amount of feed steadily increases as the weight of the fish increases. It's necessary to put enough money aside to cover the cost of feeding them for at least five months to receive a good profit. Anything less than that may not be worth raising them.
Once the tilapia weigh 500 grams (just over a pound), they are small but a salable size. If you decide to grow them on, restaurants will be interested in purchasing them. The larger the fish, the higher price per kilo you can get.

tilapia-feeding

Commercial Fish Pellets

We have heard of people who buy tilapia and feed them on bread and anything else they happen to have as scraps from the kitchen. Doing this won't get your fish to their correct weight as fast, and it could damage the quality of the water. Commercial fish food is the best choice for rapid growth. The higher the protein content, the better the fish food. Commercially purchased fish feed contains a balanced diet for the fish.


We buy our fish food in 25-kilogram sacks, and we are fortunate as the factory is only a short drive from our farm. The advantage of this is we never have a rodent problem. I know one fish farm locally that keeps large amounts of food on the premises; they have a big problem with rats. They buy poison to control any potential infestation. The chance for cross-contamination is a real risk, so in my opinion, cats or terriers would be better for controlling vermin.

Saving Money on Feed Costs

As I have previously mentioned, feeding tilapia is expensive, and it is many months before you will see a return on your investment. That said, there are things you can do to save money on your feed bill. If you have plants or algae in your lake, the young fish can survive on this.
Delayed feeding can be used when there is sufficient algae in the water.

The other option we are trying here on our farm is, every other day feeding. This will be our first harvest since implementing this new feeding regime. Our first impressions are positive. We've had a test weigh and were pleased with the results. According to other articles I have read, using this method can result in a 10 percent reduction in weight over the same period. This is where duckweed comes into its own. This high protein plant keeps the protein levels up on the days the tilapia don't get the commercial feed. They tend to graze at the duckweed, whereas with the pellets, they attack them with a vengeance.

Duckweed ponds

Duckweed ponds

Using Duckweed as a Tilapia Food

Here on our farm, we are using duckweed. This is something to watch as a potential tilapia feed, as many people and animals are eating it in Asia. Its high protein content makes it a powerhouse of a plant. It doesn't offer a complete range of nutrients needed to provide the tilapia with a balanced diet but as a supplemental feed, it's ideal.

We feed our tilapia every other day with duckweed. This is sustaining them without pellet food for a day, giving them extra protein, and cutting our food bill by half! When you have several thousand fish, the savings can mean the difference between a profitable business and one which struggles.

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

Questions & Answers

Question: What is the depth of your fish cage?

Answer: They are approximately 1.2 meters deep and 2m x2m and also 3m x 2m.

Question: Can tilapia eat farm plants and bread?

Answer: The answer is yes. However, you have to ask yourself should they, and the answer is no. You not only need to think of the fish, but also the quality of the water. You don't say what type of 'farm plants' but I would err on the side of caution. To clean a lake if that is where your fish are, is more difficult than maintaining a healthy balance. If you have too many fish or are putting in food that isn't consumed, you could be opening yourself up to problems.

If you develop water quality problems, not only will your fish be more susceptible to illness and disease, the quality of the fish and growing rate is reduced. If there is too much vegetation, you will likely develop a problem with algae, and although the fish will eat this, it could become a major problem.

Question: We live in Zimbabwe we cannot get pellets what is the way to go forward in feeding?

Answer: I can suggest a couple of different things. One is reaching out to farming and business agencies in your area and explaining your dilemma.

We used duckweed every other day to supplement our tilapia feeding. For this, we made duckweed ponds and grew it ourselves to have a continual supply. Although it cost us to dig the shallow lakes, the plant was free and saved us half of our feed bill.

The other way is to make tilapia pellets yourself.

I need to tell you upfront, I have never done this. We always purchased commercial feed. However, tilapia are hardy and will no doubt grow on what you can produce. There is publication, it's targeted toward children but you may find it useful about how to make your own feed. http://www.ctsa.org/files/publications/AmerSamoa_C...

Remember, tilapia that are swimming wild in a lake or river, are eating what they find. The idea of using pellets is to get them to a marketable weight sooner. What you don't want to do is to ruin the quality of your water with poor quality food, or too much food.

Question: Can Tilapia be entirely be fed with duckweed without a commercial fish meal?

Answer: If you think of what a tilapia would feed on naturally if not in captivity, it would not choose only duckweed. If you are farming tilapia then it is more cost-effective to feed it commercial fish pellets as well. The result will be a faster-growing and healthier fish. Duckweed alone may keep it alive but you want a healthy fast-growing fish. Commercial fish food has all that is required or healthy growth.

Question: Is it normal to reduce a tilapias' daily amount of feed at the stage of the 19th week? After the rate goes up and down?

Answer: I have included the information from the type of food we use here in Brazil for our tilapia. Although the pellet size is the same, the ingredients may be different depending on whether it was a fattening up food, or a finishing feed.

Depending on the manufacturer, their guidelines may be different.

When you decide on the brand you'll use, contact their agent who will discuss with you, what type of feed you'll need and the quantities.

Question: What is the name of young tilapia's feed called?

Answer: It is a powder, so you should ask for tilapia fry powder. The next stage will be a crumbled mixture, and then you'll be on to pellets. Even at the pellet stage, there are many different sized pellets for the tilapia as they grow. Using the correct feed for the weight and age will get your fish to market in the shortest time.

Question: The local fish farm here in Iowa will eventually have 3 million fish. How realistic would it be to have duckweed ponds to feed a farm that size every other day the way you do?

Answer: Great question. I'm not sure I can answer it fully as our farm has fewer fish. However, there are a few things I can think of to take into consideration.

Firstly how fast will duckweed reproduce in Iowa? One of the key reasons duckweed is a 'tilapia superfood' is because it grows so quickly. If you can get it doubling its volume in a few days, then it may be worth pursuing.

Another consideration is the harvesting of it. We used a swimming pool net and a plastic box. We then carried this to a rowboat and a kayak where we distributed it in the cages. This was the reason our ponds were long and narrow, so we had access from both sides. For 3 million fish you will need mechanized help. Off the top of my head, I would say a large fine net that can be dragged through your pond with a tractor. The key is to remember that labor is expensive, so use the most cost-effective way possible. Although duckweed is light, when you are lifting water, especially if it is a distance away such as at the end of a handle as ours was, it becomes heavy as the water is draining out of the net.

Also the tilapia will grow slower if they are only getting their commercial feed every other day, even with the duckweed as a supplement. Here again, you have to weigh the savings against the costs of electricity if you're running pumps, wages, and a fluctuating market price.

Question: Is that feeding chart in the article, and more particularly the size of the fish after X weeks, copied from somewhere or are they the results you have achieved? Your growth rates look very quick. What temperature are your Tilapia ponds?

Answer: We used a commercial feed from a Brazilian company called Guabi. The information you see was from their company and specific to the type we used which was a mid-priced range.

I don't know the temperature of our lakes, however are daily temperature is always (year round) about 30°C (87°F) so the water is always warm.

Question: How can I make my tilapia produce only male fish?

Answer: Your tilapia will produce both male and female fry. What you need to do is give them 17α-Methyltestosterone in their feed. It is recommended you start on day 10 post-hatching. However, check with the manufacturer for the duration and best practices.

We bought our fry when they were 30- 50 grams so ours had already been altered.

Question: Is the growth chart you published above reflective of your experience feeding duckweed every second day, or was it copied from a food producer based purely on commercial feed input?

Answer: The chart is only if you were feeding a commercial diet. Also, it is possibly specific to only the feed produced by Guabi. Wherever you purchase your tilapia food, they should have a feeding chart similar. Ours was printed on the side of a 25kg sack.

By feeding duckweed, you can expect a slower growth rate, however, you'd be saving half the feed costs.

Something else we did, was to sell some of the bigger fish as we went along. This brought back some revenue to help fund the ongoing feed costs.

Question: Can I feed my tilapia crickets or earthworms?

Answer: Yes, you can. You don't say what type of set up you have for rearing them but always monitor what they eat or leave. Try only a few and see if they readily eat them. What you don't want is food, be it natural or commercially made, rotting. Always take into consideration the quality of your water.

© 2012 Mary Wickison

Comments

Mary Wickison (author) from Brazil on January 16, 2020:

Yes they can. One advantage is you can see your livestock.

This advantage didn't occur to me until we put some of our larger fish into our tanks. What we were now able to see surprised us. We had one female in the tank and because of this none of the males were eating. One, alpha male, was protecting her in a corner, while all the others were only interested in mating. Of course if they aren't eating, they aren't putting on weight.

Another advantage is better food control. In a lake or cages, uneaten food falls to the bottom of the lake which eventually may cause problems.

Cement tanks will be easy to clean and can be drained once the fish are sold.

Ensure you use a waterproof sealant that is suitable for aquatic life. Also depending on the depth, keep a check on the temperature of the water. You should be having fresh water flowing in which will aerate the water. However depending on the number of fish, it's likely you will need more aeration. Consider a 'bubbler' an air stone, or a diffuser which is like a large shower head with fine holes..

We used a series of diffusers across eight tanks plus an industrial blower. Although this was effective, depending on your cost of electricity, it could prove not financially viable.

Nshom on January 16, 2020:

Madam am grateful for this info can tilapia be raise in a cemented pond if so what are the advantages?

Mary Wickison (author) from Brazil on October 13, 2019:

The chart above gives that information. It is per 1000 fish per day. It soon becomes apparent that it expensive to bring all the fish to a given weight.

Ways to save on the cost, is feeding duckweed, delayed feeding, and selling some fish to reduce the amount required. It is also worth noting, that the long the fish are with you, the more you have invested in them. If they die, due to illness, thermal shock, poor water quality etc. you receive nothing back.

With that in mind, you may wish to sell them sooner. Locally there is a tilapia farm who sells tilapia at 500g. The benefit of doing this, is a quicker return on your money. Their clay based ponds, are then drained, cleaned and ready for the next batch. Also because of the limited lifespan, breeding isn't taking place.

Enesokos Aquaculture Solutions on October 12, 2019:

How much feed is need on average to raise 1000 Tilapia fish for eight months?

Mary Wickison (author) from Brazil on October 06, 2019:

Hi Fatima,

I'm not familiar with azolla.

Regarding duckweed, it was trial and error. As I mentioned in the article, we would have one day feeding commercial pellet feed and the next feeding them duckweed.

If there was any duckweed still remaining we would use less the following day. We used a large plastic box and put in amounts the size of a football into each cage. Our cages has 600 fish in the 2m x 2m size.

Fatima Grace on October 06, 2019:

Hi... Im from Philippiness , my daughter will conduct experiment on tilapia natural food. They will use duckweeds and azolla. Can you help and teach us how much duckweed and azolla can be use to feed tilapia. Thank you for the help.

Mary Wickison (author) from Brazil on May 23, 2019:

Hi Joseph,

You don't mention where you're located. You should go on the internet and type 'tilapia food' followed by name of your area. If nothing comes of that, go to a feed store or pet shop and see if they carry it.

If they do, buy a sack so you can get the manufacturers information. Then contact them directly. When we did this, we were able to get helpful advice and a much better price.

I would also suggest sourcing duckweed and growing some. We were able to reduce our feeding bill dramatically using it every other day. The cost of it is virtually free.

joseph acquaye on May 23, 2019:

i want tilapia feed to buy..please direct me where i can get some to buy

Sudip Bhattacherjee on April 06, 2019:

Madam,i'm going to start monosex tilapia in an earthen pond faciliated with aeration through blower and in semi biofloc system.would you please advice me about the stocking of fingerlings/m2.The fish will be growing upto 200gms.It is tropical country.Regareds,B.Sudip.

Mary Wickison (author) from Brazil on December 31, 2018:

Hi Willy,

I'm impressed by the items you've tried. Something else we briefly considered were algae and also seaweed. Both free, depending on where you live.

We also live in an area with sugar cane, but we never thought of trying that. Here much of it is made into bio-fuel as a good portion of the cars run on it.

I had to laugh at your lobster sandwiches. I can't imagine trading for a ham and cheese! Oh how times have changed.

I too think we may one day see "exotic lemna" on the menu.

I hope 2019 will be a year filled with good health and happy times for you and your family.

Willy Hese on December 29, 2018:

Cheers Mary,

I have the great feeling I touched a new milestone by finding your web page and off cause your reply. Thank you for that.

As you said the taste of Tilapia fed with duckweed improves as well I'll make a test by adding it to our recipe asap and in a few month I'll post a result.

here a little insight of our "test-kitchen" on our path to find the "ultimate, sustainable and free fish food"

We tested so far sugar cane which is available all around Thailand mixed eggs into the shredded paste (careful as too much eggs makes the pellets sinking!) and boosted the appetite of our Tilapia with garlic.

Just a few garlic cloves making them going ballistic on the food pellets without changing the taste to the negative.

Duckweed tastes not bad (wolffia globosa is sold as delicatessen in Thailand) and as dried meal I reckon it supports the floating capability of the pellets.

Adding carrots seem to have also influence on the coloration, appetite and especially taste.

But carrots are expensive and sinking so it might be in a commercial sight a step back for large scale farming.

Regarding Weeds and Pests:

As a Grandson of a Fisherman I grew up with lobster sandwiches in my lunch box at school back in the end 60's. I always was trying to swap them against Ham and Cheese Sandwiches with minor success. Nobody wanted the food of the poor people.

I guess there will be coming one day the Duckweed will leave green spots on the white table cloth of the posh restaurants around the world.

...and so might be Tilapia, it all depends on trends and promotions..

Best regards and a successful new year 2019/2562

Willy

Mary Wickison (author) from Brazil on December 28, 2018:

Hi Willy,

Yes, it is the Lemna minor. You're correct in thinking that it is considered a weed. Like most things in nature, we are still learning of the beneficial properties of many plants and until we find a value, we class them as a weed.

There are many people who are plagued by what they consider a nuisance weed, when in fact it has a value to someone. Such is the case with duckweed.

Good luck with your farm.

Willy Hese on December 28, 2018:

Hello Mary,

thanks for all the insight as its very informative and helpful also for our plans to build up an Aquaponics Farm in Thailand.

Many things you wrote we can confirm as we have made a test system about 6 years ago.

We still are a bit thin of knowledge when it comes to duckweed.

I was looking for the variety Wolffia globosa (common in Thailand) and Wollfia arhiza.

Unfortunately both varieties gave us huge struggle to grow commercially.

At first glance I would say you have in your ponds the variety Lemna Minor which we thought its not suitable for Fish Food but learned now it is. And that grows also in our test systems as a weed.

Can you confirm that you have a Lemna and not Wolffia variety in your ponds?

Mary Wickison (author) from Brazil on December 01, 2018:

Because we were using cages, we started feeding ours duckweed when we first got them. We bought our fish at 50 grams. If you were rearing in a lake, as we did the first year, we bought smaller ones at 30 grams.

The answer really depends on your set up. If you have algae in your lake, your young will eat that. In my article I mention delayed feeding as another way to save money on tilapia feed.

If you had very small fish, I would personally opt for the commercial feed as it wouldn't be worth the time involved to process it. The joy of duckweed is it's free and easy to grow and harvest. If you begin to process it by chopping, freezing, or drying, the value of it lessens because your time has a high value.

Regarding the second part of your question, I'm not sure what additives you mean. Because we were feeding commercial feed on one day and duckweed the next, we felt confident that our fish were receiving the nourishment they needed.

Since ours were in cages, there was less chance of them eating naturally occurring food, this is why we continued to feed the pellet food.

Mahmoud Hussein on December 01, 2018:

What is the suitable size of fish to eat duckweed and is there any additives to put for duckweed

Mary Wickison (author) from Brazil on November 19, 2018:

Hi Lance,

The ponds produced it continually and there was never a shortage. We have the perfect growing environment for them as our weather is a constant. We are 3° degrees south of the equator so year round our weather is 87-90°F around 30°C. The amount of sunlight is about the same year round as well.

The duckweed reproduces so quickly that even if we took out half a pond of duckweed, in two days, it was completely covered again.

Lance Keller on November 19, 2018:

I am a business teacher and my class is doing research for a local Tilapia fish farm. In regards to the ponds you have pictured in this article. How often do these pounds produce duckweed? What is the turnover rate? Thank you.

Mary Wickison (author) from Brazil on September 05, 2018:

Hi James,

First and foremost keep your water quality as good as possible.

If cash flow is a problem, harvest early and/or frequently to reduce the numbers and get some cash coming in. Too many fish will result in stunted growth and unplanned breeding.

Duckweed is a free option to supplement your feeding regime.

James Agbenorku on September 05, 2018:

I have a fish farm in Ghana and I need more knowledge as to cut down cost but boast production.

Thanks

Mary Wickison (author) from Brazil on December 18, 2017:

Hi Josephine,

The feeding chart I've listed is the recommended feeding for either pond or cages. However, these are just guidelines. If your fish don't eat it quickly, cut back on the quantities. Every pellet not eaten is money down the drain! The fish will be affected by many things such as quality of the water, breeding, weather and even if it is a full moon.

The number of feeds per day we based it on how old our fish were. We bought our fish when they were 50 grams. That means they were 8 or 9 weeks old. Then we followed the chart. It isn't possible to do it only on weight, especially if you have them in a pond. As some will grow more rapidly than others. If your pond isn't drained and all fish removed, you could have too many fish all competing for the food. This will lead to stunted growth in your fish. They will get slightly bigger and weightier if separated.

If you have your fish in a pond, frequent netting should be done to get rid of small ones. Depending on the size in the cull, we give them to our cat or the chickens. Even burying them is beneficial to your vegetables (fish meal). I know it seems counterproductive but you want to have large fish.

I don't know how much one tilapia would eat but if you total up the right hand column until the weight you would hope to sell the fish at, and then divide it by 1,000 that should give you a rough idea.

Thanks for your questions and let me know how you get on.

Josephine on December 18, 2017:

how many grams or kgs of feed does one tilapia take in the 8months?

Regarding the feeding chat above, is the "No. feeds per day" column the feeding rate per body weight in percentage or its the number of times a fish is fed per day?

Thanks for the sharing spirit.

Josephine on December 18, 2017:

Hello Mary, I enjoy growing together with you in the tilapia farming production. My question would be, is the feed chart of tilapia ponds the same as for tilapia cages?

Thanks

Pablo Garcia on January 20, 2017:

Thanks for your response. Very Helpful!

Mary Wickison (author) from Brazil on January 13, 2017:

Hi Pablo,

Feeding duckweed has many benefits. Not only are you reducing your feeding costs by half, but I feel it is also beneficial to the taste of the fish and the water in your lake.

I think any time a natural product, such as duckweed can be used, the flavor will be better. If you use chickens as an example, free range chickens who have a variety of natural foods taste better than one raised on just factory produced pellet food. The same is true for fish.

I also believe a natural diet is better for the quality of the water, as the fecal matter will also be more vegetable waste. If you are farming in a river the difference might not be noticed as the water is carried away. If however, you are raising yours in lakes, ponds, or tanks a build up of fecal matter can lead to poor water conditions. Algae can begin to grow and although tilapia will eat the algae, it starves the water of oxygen at night. Let me tell you, there is nothing worse than seeing your fish which you have fed for months, on the surface gasping for air.

If you feed every other day, you can expect a 10% reduction in weight, however when you offset this against the cost of food it works out better.

As always though there is a downside to this waiting time. As you probably know, the tilapia can start breeding at 4-5 months of age and this is why many people sell them before this time otherwise you can have too many fish.

Here on Hubpages I have an article about our duckweed ponds.

Thanks for reading and good luck with your fish.

Pablo Garcia on January 12, 2017:

Hello! Awesome article. I have a tilapia farm in Florida and I want to cut cost on food. Also, I want to use the duckweed that grows in a pond separated from my fish tanks. I would like to know how was the output of feeding the tilapias every other day? (one day with commercial food and one day without food). And also, the result with the method of feeding one day with commercial and one day with duckweed. Thanks for the information!

Mary Wickison (author) from Brazil on August 04, 2016:

Hello Treeman,

It sounds like your project is a success story. Do you have a website related to your school's project?

Regarding birds taking the fish, we use cages with a plastic mesh on top. The fish which are swimming freely in the lake are a strain on the lake and we are thankful that herons, egrets and kingfishers take them.

We also have predators in the lake, peacock bass and a fish call a triara, to minimize the numbers.

treeman on August 03, 2016:

The school's tilapia project keeps growing in scope. The students sold enough of the estimated 100,000 tilapia they raised last year to cover the costs and make a profit. Some of the brood stock are over five pounds. They put string with flagging tied to it to discourage raptors. Thanks for all the information.

Treeman on August 15, 2014:

Yes it does. We spawned them inside in tanks and moved them into the ponds in May. We will need to harvest them before the ponds cool down. That is where your chart helped a great deal. It allowed us to estimate finish size at a certain date. This summer has been very cool and we lost some growing time. Next year we will start with larger fish and attempt to sex them before stocking in the pond. We also sold many fish to control pond growth. All the ponds are better except one. I later found out it is forty years old and is over the tipping point as it is changing into a wetland. It also is being fertilized by a large flock of geese. We also sold fish for people involved in aquaponics. It has been a wonderful experience for the students and we still have the harvest and marketing ahead of us. The school has committed to expanding the project. We are planning on moving into a 28x50 foot building. The students will be planning and building the hatchery. They are also using heavy equipment and survey equipment to build two more ponds. They operate dozers, track hoe, backhoe, skid loaders, tractor and material handler. We added a second teacher this year because we had more students wanting to enroll than we had room. Both program are at full enrollment already for this school year and unfortunately we are turning away students again. Many of the students go on for further education in wildlife, fisheries, forestry, enviromental science and engineering. Our school also is located inside a booming shale gas drilling area. Many students go to work in the oil and gas industry as gps techs, equipment operators, reclaimation and resource conservation.

Mary Wickison (author) from Brazil on August 15, 2014:

Hi Treeman,

We only buy in the fish at 30-50g. The buyers use hormones though.

May I ask, how are you keeping your fish alive over winter, doesn't it get cold in Ohio?

Treeman on August 15, 2014:

Do you use hormones or hybridization to create your all male population

Mary Wickison (author) from Brazil on August 07, 2014:

This is based on an all male (or as near as possible) population. Female tilapia are a problem to have in the pond for a few reasons.

They can start to breed at 4 months (depending on the species). Because they are mouth brooders, where they hold the eggs and the small fry in their mouth, they don't eat and because of this they don't gain weight.

Plus, having them also causes the males to eat less. This was something we only noticed when we had them in shallow tanks where we could see them. The female was in a corner with one male, almost guarding her. All the others were trying to attract her and weren't eating as a result.

Another problem is, when they begin to reproduce there is too much competition for food and you may get stunted growth as a result. If you have enough space, keep thinning out the population. Although the fish may be smaller, they can still gain weight and that is what they are normally sold on.

This is one reason people like to use cages for their fish, the eggs fall through, and aren't fertilized. However, rearing in cages also has its disadvantages.

Treeman on August 07, 2014:

I was wondering if the chart is based on an all male population of fish or a 50/50 mix? Thanks The growers of tilapia in Ohio find the chart very helpful for projecting costs and finish weights.

Treeman on August 04, 2014:

300 lbs was not enough to let the duckweed take off even though we kept the 1400 fish in that pond well fed with high protein pellets. They ate their cover. In a different pond that has a history of total duckweed cover, the fish are eating it to the shore. If the duckweed starts to take off growing out of control we skip a feeding and the duckweed goes away. The fish in that pond are growing faster than any of the other four. It is working but duckweed can be terrible for a pond. It is like playing with fire, easy to get burned if you lose control.

Mary Wickison (author) from Brazil on August 03, 2014:

I understand your thinking regarding the duckweed however it could very quickly cover your pond completely. This will cause a problem for your pond and your fish. It will use too much oxygen and without aeration in your ponds your fish will suffer.

I have seen nets suspended above ponds to keep the great egrets, herons etc. away. I have also seen CD's strung on line across the ponds to scare them off.

Fish cages are also another option although the more fish you have in a cage, the higher the risk of disease. In the photo above we had two sizes of cages. 3meter x 3m and also 3m x 2m. The 3x3 had a capacity of 900 fish and the smaller a capacity of 600.

If you have to get rid of your duckweed, this too could be a money maker for your school. There are people who sell it through Ebay. Also people who have aquariums buy it. It is a great food not just for the tilapia but also for chickens, as it is said to produce more white meat .I also imagine pig farmers would be interested in it.

I have read it is consumed by people in some countries in the far east as well.

Let me know how you get on.

Treeman on August 03, 2014:

The fish are eating and growing. The eagles and ospreys have found our ponds. We put 300lbs of duckweed in the hardest hit pond to make it harder for the birds to see the fish.

Mary Wickison (author) from Brazil on July 14, 2014:

Hello Treeman,

What a wonderful school project. You can incorporate so many interesting learning avenues from this.

So pleased you found and enjoyed the page. Keep us informed of the progress. If you are writing about it, let me know and I will drop a link to it on this page.

Thanks again.

treeman on July 14, 2014:

Thanks for the great info and chart. We are currently raising 4000 in ponds at our school in Ohio. Your chart perfectly matches the data from our ponds and tanks. Best info we found on the net.

Mary Wickison (author) from Brazil on September 09, 2012:

Hello Peggy,

Thank you for the tweet and vote.

When they reach the correct size, we either sell them locally or we call in a buyer who pays less but buys all of them. He brings a team of 4 people who will put them into ice water in a 500 liter water tank, which kills them and then they begin gutting, scaling, and weighing. There is caçhaca being drank, lunch of BBQ tilapia and rice and at the end of the day, money changes hands.

If we sell locally, a neighbor puts them on the back of his motorcycle in bags and takes them to local shops. He has managed 40 kilos on the back. He always looks a bit unsteady going down the sandy drive but he is accustom to driving in it.

I haven't written a hub about that but I should. Thanks for the idea.

Peggy Woods from Houston, Texas on September 09, 2012:

I found this hub very interesting. We like eating tilapia fish and learning about how you are raising them for sale drew my attention. Sounds like you are leading an interesting life! Once the fish are ready for market, what happens next? Have you written another hub about it? Up votes and tweeted.

Mary Wickison (author) from Brazil on August 07, 2012:

Hello Naeemebrahimjee,

Thank you, I am pleased you found it interesting. Thank you for stopping by.

Mary Wickison (author) from Brazil on August 07, 2012:

Hello Teaches 12345,

Well you never know, I am sure in Florida the temperature is perfect!

Thanks for the vote up.

Mary Wickison (author) from Brazil on August 07, 2012:

Hello Pao D Panlilio,

How interesting. My husband used to sell them as aquarium fish many years ago. I personally had never heard of them before arriving in Brazil. You are right about the high protein content, it is important for growth.

Thank you for your input.

naeemebrahimjee from London on August 07, 2012:

This is a very interesting hub. As a person with a keen interest on fish this really caught me eye.

Excellent job.

Dianna Mendez on August 06, 2012:

This is quite an interesting read on the raising of tilapia. I do love to eat this fish, but not sure raising them would be up my alley. Voted up.

Pao D Panlilio from Caloocan on August 06, 2012:

great hub im not in the tilapia business but i raise them as feeders for my aquarium fish, but i feed them the cheapest dog food with high protein content