So you need more fish…
Say you just harvested 100 lbs of your tilapia for a local restaurant, or a couple died of old age. Or maybe you accidentally froze one of your fish tanks.
Maybe your current stock is just getting old and less productive and you want some young fish in there to keep nitrification pumping along.
Regardless of why your stocking density is low, you’re going to need to replace those fish, right?
But buying fry (baby fish) can get pricey, and as a start-up farmer, that’s always not the most appropriate option.
So you decide to breed your existing stock. That’s great! But… how?
Here’s what you need to know.
First of all: How do you keep your tilapia from breeding?
“Wait, wait; why would I want to keep my tilapia from breeding?”
We just decided that breeding was a good thing, right? So why not just let your fish breed all the time?
Because when Tilapia are getting environmental cues to breed, that becomes their top biological priority.
This—unless you want fry—is bad news for you. Breeding tilapia will stop gaining weight and if unmanaged, can cause all kinds of trouble. Male tilapia show extreme aggression to the fish around them and will kill other males and other females.
Quick tip: If you choose to isolate your breeding individuals in a brood tank, always put in more mature females and fewer mature males, so that the male is less likely to damage the female. (A good size ratio is about 20 to 6 inches.)
There are two ways that you can keep your tilapia from reproducing.
- The first is keeping your water cool. (You can read more about ideal temperatures here.)
- Keep your tanks in the dark. As you’ll see, light acts as a cue for the fish to breed.
Selective breeding
Before you start breeding, select the stock that you want to breed.
You’ll want to identify several traits that you value. (For us, a valuable trait is cold tolerance. If you’re selling your fish, that trait may be size.) Then, you want to isolate those traits.
You can isolate a trait by first selecting some candidates from your tanks and putting them in a separate tank, and applying a factor that eliminates the individuals that don’t possess that trait.
For cold tolerance, this means that “You freeze the tank and the ones that are left over you breed.”
P.S. – This is a very loose definition of selective breeding! There is a certain amount of chance involved. If you’re in a hurry to get a specific breed, you’re better off getting tilapia from a breeder.
Optimal conditions for breeding tilapia
Okay, so you know how to keep your tilapia calm. How do you get them to breed?
Just like you keep the water cold and the lights off for calm tilapia, you can use warm water and light as an “on switch.”
Both the warmth (75–85 degrees) and the light cycle (at least 12 hours a day) act as environmental cues to your fish that it’s time to make fry.
There’s one more thing that you need to facilitate reproduction for your fish: a substrate.
Female tilapia “mouth-brood” their fry—that is, they lay unfertilized eggs on the bed of the lake or tank. The eggs are then fertilized by a male, and the female returns and scoops the eggs into her mouth, where she broods them until after they hatch.
In the wild, tilapia use the bed of the body of water as a substrate. You will have to give your breeding tilapia a substrate like a gravel bed for them to lay eggs.Of course, the female needs a safe place to lay those eggs. In conical tanks like ours, laid eggs would drift to the bottom of the tank and be drained away or picked up by an SLO.
Even in flat tanks, the eggs drift and are both poorly fertilized and difficult for the female to collect.
You can compensate for this by giving the fish a substrate of some kind—something like a gravel bed where water movement is slowed and the eggs are sheltered.
Separate fry from mature fish
Once the fry have hatched and emerged from the mother’s mouth, you’ll want to separate the fry from the mature fish so that they are not preyed upon.
You can do this either by netting the mature fish out of a fry tank or vice versa.
An alternative option is producing fry manually—obtain the eggs and sperm by milking, then combining the two in a container.
Ready to bump up your stocking density?
Good luck!
What other questions do you have about breeding tilapia? Leave them in the comments below!
I want to start a fish farm, but would like to start small and start with a breeding pair
How long does it take Tilapia to lay news eggs after delivering new fry? Suppose the Tilapia just gave out the new hatchlings and you separate the fry from the mother, how long will it take for it to start laying eggs again?
Than you
Hi there,
In great conditions, your fish should lay new eggs as soon as the last batch of fry is gone, or about 1–2 months.
Two weeks, feed them well.
Having selected tilapia for brooding which were all female how then do you get male ones?
sex reversal through hormones
how long does it take for the eggs to hatch
10 to 14 days.
Is there an ideal size (length) of the Tilapia for when they start breeding? And is there a length of when their reproduction drops off?
I have set up a breeding tank with 5 females and 1 male. Have more than enough babies. How many years can I use this group of fish to produce fry? I want to replace them before they are 2 old to reproduce. They are 15 months old. Blue Nile Tilapia.
Hi Doug,
Tropical fish will keep breeding until they die—in fact, females often die in childbirth, and males tend to die of old age. Keep in mind that good environmental conditions are critical for fast and healthy reproduction and that this will likely affect how many rounds of fry you’ll get.
Hi, I just started with 25 fingerlings and all but one has remained. This one has been robust and is biting/chasing the other fish all the time. To date he is 4 1/2 inches long (4.5 months old since I acquired him as a fingerling) and just 2 weeks ago started to eat less and less and doing all kinds of strange movements: swirling around, pointing his head vertically downward as though kissing the bottom of my aquarium, dashing up and down violently and brushing his body on the side of the aquarium.
Is he sick or is he in a breeding state? How long before he gets back to a normal eating/swimming mood?
Your kind and valued advice would be appreciated much.
Sincerely,
Joe
Hi Joseph,
It sounds like it could be some sort of parasite and/or swim bladder issue. The scratching against the bottom of the tank is called “flashing” and it is literally the fish scratching an itch (usually caused by a parasite).
The floating/swimming weirdly sounds like swim bladder problems. Fish use their bladder to orient themselves, and when it develops issues, they have trouble controlling the direction they move in. One cause for both is water quality.
This could also be the cause of the first 24 fish deaths depending on what happened. If the remaining fish ate them, it could have been a gender issue.
Could I Isolate fish by there gender?also how much fry are eggs are laid in a batch?
Hey there,
Yes, this is possible. The total number of eggs will depend on species, age, and environmental conditions.
hello how much space does one tilapia fish need to breed in m³ please
Hi there,
Optimum stocking density for breeding ranges from 5-10 fish/m2.
Hello my male is ready to breed, He already prepared the nest but he is beating all the females.
Is it normal? I have one male with three females and it seems like the females don’t want to breed
Hi. I have a stock of red Mozambiquen Tilapia for my Aquaponic vegetable system and would like to breed new stock, but when I put a pair in a breed tank they lose all interest in feeding. I make sure the water is aerated and filtered in a way as not to create water disturbance, and a heater to maintain the temperature at 15Deg C. The tank holds 49 litres. Why would they lose interest in feeding when in the pond they eat like crazy?
Hi Charles, they are likely not eating because they’re breeding! They are mouth brooders. So when they start to breed (which happens almost immediately when mature males and females are in the same tank), the males become hyper-aggressive to other males and stop eating and the females start to mouth brood the fertilized eggs.
I have a small (600l) backyard aquaponics system and cleaning out my radial flow separator (rff) this afternoon I discovered about 20 little fry swimming around. I cleaned the pump housing and RFF out two days ago and they weren’t in there yet, so these are obviously very newly hatched. I guess being so small the pump sucked them in and dropped them off in the RFF.
In any case, I caught the the fry and put them in a 5l bucket with some water taken from the fish tank. Apparently they don’t feed for the first couple of days so I’ll start feeding them tomorrow evening. I was thinking to simply powder some of my normal feed.
I wasn’t planning on breeding with the fish yet (my system is just over a month old) so I’m a bit unprepared by these developments. Is there anything else I should be aware of or watch out for? Any other helpful advice and tips would be greatly appreciated.
Hi Phillip,
Keep an eye on the conditions inside of your water tank—this is likely what inspired the breeding. If you do plan on keeping these fish and adding them to your system, make sure that the water conditions in the bucket are appropriate (e.g. enough DO, right temperature, etc.).
I have a small aquaponics system and cleaning out my radial flow filter (RFF) this afternoon I discovered about 25 little fry swimming around. I cleaned the pump housing and RFF out two days ago and they weren’t in there yet, so these are obviously very newly hatched. I guess being so small the pump sucked them in and dropped them off in the RFF.
In any case, I caught the the fry and put them in a 5l bucket with some water taken from the FT. Apparently they don’t feed for the first couple of days so I’ll start feeding them tomorrow evening. I was thinking to simply powder some of my normal feed.
I wasn’t planning on breeding with the fish yet (my system is just over a month old) so I’m a bit unprepared by these developments. Is there anything else I should be aware of or watch out for? Any other helpful advice and tips would be greatly appreciated.
Also, I see there’s another female with fry in her mouth. Should I leave her in among the other fish, or do I remove her to a different tank?
If you plan on keeping the fry, move them to another tank.
I just started a breeding colony; I have 1 male and started with 4 females. But my male is a really aggressive jerk… so I ended up going up to 6 females to split up the harassment between more fish. 2 of my females have turned really dark; or at least their faces. They are not carrying because they eat with the rest of the group; however outside of eating they kinda take their own spot in the tank and chase everyone else out of their zone; except the male. Despite being small he doesn’t take crap from nobody.
Is there a reason those females are darker? Could the make fish be too aggressive and stressing them out? I have 3 other males that are a little bigger but 2 of them are pretty passive. Just wondering if I should swap fish or just keep waiting? Been like 2 weeks with no egg holding.
The male gets a almost a pinkish color with the tips of his fins all turning black, I assumed this was breeding colors? He does sometimes push the females into his pot at the end of the tank or chase them till they go in there but nothing seems to happens from there.
Hi Jay,
Here is an article you may find helpful: http://www.tilapia-farming.com/2013/02/19/tilapia-breeding/
Here is another from Dr. Rakocy—I recommend looking into his work more as he has lots of research about aquaponics and fish to learn from!
Finally, here is a link to a few Google Scholar articles that came up in a “tilapia breeding behavior” search.
Well, I hate to admit it, but I’m stumped. I set up a separate brood tank a while back and started trying to breed Blue Tilapia. So far, I have to call the effort a failure. I’m using a food-grade polyethylene, fifty gallon capacity tank, which is independent of the rest of the aquaponics system. Since it’s therefore not benefitting from the filtration afforded by the plant beds, it has its own filtration system, which is rated for a larger capacity tank than I’m using, and is cleaned daily. Aeration is also somewhat oversized. Water parameters (PH, ammonia, temperature, and oxygen) are all measuring textbook perfect. There’s a couple of inches of thoroughly washed, PH neutral gravel substrate. I’ve tried providing shelter (flower pots, 4″ perforated and unperforated PVC pipe, etc.) and also not providing any.
To make a long story short, I’m obviously missing something. Fish keep dying. This is my sixth attempt. I’ve tried varying numbers of fish, varying sizes and ages, varying male-to-female ratios, and filling with both new water and water from the main system (just in case something subtle might be shocking the fish). The fish seem absolutely healthy when they go into the brood tank.
In the latest attempt (yesterday), I started with a male which has survived the previous couple of attempts just fine. I only put in one female with him this time. Previously, following a failure, I’ve thoroughly sanitized the tank and equipment and started with new fish. This time, I wanted to see what would happen by retaining the survivor, and not radically changing the environment. Well, this morning, both fish are alive but I can tell that the female is already on her way out. The male looks fine. Again, several different males have been used in the course of this experiment.
As a totally separate thing, and by way of a ‘control’ of sorts, I also use a smaller purge tank when harvesting fish. Conditions are identical to the tank I’m trying to breed in, and I never lose fish there, even if I leave them in it for several days.
I’ve read everything I can get my hands on to try and determine what’s going wrong. Any thoughts, insights, hints, etc. are very much appreciated. Please feel free to ask any questions that might lead to a better understanding of this problem. Thank you!
Will tilapia lay egg year round?
Yes!
I have just finished constructing some fish ponds. What is the stocking density for nile tilapia?
I recently heard that tilapia fry can be used as a food source for largemouth bass in northern lakes and ponds (Ohio in this case). I was told that mature tilapia reproduce every 30 days, which provides plenty of food for the bass during the warm summer months. However, all of the tilapia will die when the water gets below 45 degrees (winter season). This insures that they won’t “take over” and upset the natural fish populations. The mature tilapia would have to be reintroduced each spring when water temperatures are warm enough.
My concern is the possibility that the tilapia could evolve to tolerate the cold winter water, thereby upsetting the native fish population. Can anyone speak to this issue?
I think your concern is founded, authorities are quite concerned about releasing non-native (invasive) species into wildlife where they’re not already found. And yes, the fish you release could indeed develop cold tolerance. Even if they don’t, they may impact the waterways even during the warm months of the year. The problem is always unforeseen consequences. Look up what happened with hippos in the Amazon. In fact, the Chinese Flying Fish is an invasive species that has completely taken over many rivers and lakes in the US.
Hi! 1kg female, how many fry? and 12 months how many lift can breeding?
Thank you very much i have learnt much from this site
My question is,having built a cement pond how much substrate can i put in the pond depth wise considering other plants and nesting of tilapia
Hi, do i have to seperate my males from females in my 10000 gallon pond? will the size be really stunted? and cant you just remove fish if they become overcrowded? thanks
I am wanting to buy mature tilapia and breed them, I have a 90-gallon brood tank I want to use. How many fish would you recommend I get? Ratios of male vs. female would be helpful too!