Backyard Aquaponics

Breeding Mozambique Tilapia
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Author:  tdbrueggen [ Jan 3rd, '14, 04:34 ]
Post subject:  Breeding Mozambique Tilapia

I hope I'm not asking too much here, but was wondering if anyone could provide the basics of getting the Mozambiques to breed. As it stands, I only have four fish in total, and currently they are too small to even vent effectively. I'm pretty sure the biggest is a female, so now it just a matter of hoping at least one of the others is a male.

So I've read they are finicky on two areas; temperature and pH. Anything else? Both of the aforementioned should be easy enough to control, so long as I know what the target is. Anyone care to share from their success? Or do I have to learn it on my own? :support:

Author:  earthbound [ Jan 3rd, '14, 13:23 ]
Post subject:  Re: Breeding Mozambique Tilapia

I think the main problem will be how to STOP them breeding.... Once they get old enough, they are rampant.

Author:  bcotton [ Jan 3rd, '14, 15:07 ]
Post subject:  Re: Breeding Mozambique Tilapia

This is a cut and paste of a post i made on a different forum. It gives more information than you need.

Since my last update was not really a full new system, i'll give a little bit of bonus footage.

I did a lot of work with tilapia breeeding during this same time.

The tilapia were breeding in my stock tank but there was no fry cover to protect them and they would usually get eaten by bluegill or other tilapia almost immediately after leaving their mother's mouth.

Occasionally, i would see a few fry swimming at the surface near the side of the tank and i would be able to net out 10 or 12 and put them in an indoor aquarium to grow out.

During breading season the largest/dominant male's head turns red and they stake out their territory at the bottom of the tank. I put a lot of PVC pieces in my tank to segregate it and I ended up with 3 males that were able to make a nest/territory.

The rest of the tilpaia males and females just try to stay out of the way. You will have 3 males taking up 295 gallons and two dozen other fish taking up 5.

I moved 1 male and 3 females into an indoor 55 gallon tank(top). You can see some of the fingerlings i was able to save from the outside tank in the early days of spring. (bottom)

The male is very big for a 55 gallon tank. He thinks the whole tank is his territory and he constantly harasses the 3 females to get away. The largest female was ready before the others so her and the male teamed up to bully the other two. Overnight they shreaded the side fins of the second female and pecked at her until she no longer bothered to defend herself or run away. I removed the smallest female back to the outside tank and i moved the second bullied female to an isolation tank but she died a few days later.

When i came home from work that evening the male and female were finishing up. The female would lay a few eggs in the nest. The male would swim by and do his thing. The female would pick the eggs up into her mouth and lay a few more, rinse, repeat. Once they were done, the male changed and was very aggressive to the female and she was unable to get away. So i moved the male back into the outside tank and left the female there alone.

10 days later i came home to a few hundred fry and a proud momma tilapia. The female has not eaten in 10 days and while she shouldnt eat the fry immediately, eventually her motherly instincts wear off and her survival instincts come back, so i moved her outside and left the fry in the tank alone to grow.

Notice I was circulating water between the tanks with a pump and an overflow, but i had to stop this because the tiny fry were slipping through the overflow into the bottom tank where they became fingerling snacks.

Conclusion. I felt like my 55 gallon tank was too small to breed in. So I moved on to try another method which i will talk about below. However, i have since found out that a 55 gallon tank can be use you just need 5 or 6 females. They will school together for protection and the male tends to be less aggressive and damaging than when he can corner and isolate just one or two. The work required to move fish around in different stages was also a deterring factor. The risk of injuring the fish through handling is also worth considering.

Credit: The following technique was gleaned by reading "badflash"'s posts on the diy aquaponics forum. Not exactly his design but I wouldnt have gotten here without reading his work and information.

I stopped trying to move breeders into my internal tank and just started watching the fish in my outdoor tank. When a female has a brood she will isolate herself. her jaw starts to get bigger and she will not open her mouth. In later stages of brooding, her color changes to dark black vertical stripes that are easy to pick out.

I would net the brooding mother and drop her in a half filed 5 gallon bucket. She is usually scared and will either spit out the eggs, swallow them or (in most cases) a little of both. Once she's in the 5 gallon bucket i pick her with my hands, open her mouth to rinse the rest of the eggs out and then i set her free.


I then incubated the egg's in DIY egg tumblers powered by air stones. (This is my first tumbler design, it's improved some since) The weaknesses of this design is that the air stone is not secured [if something moves the air hose or the tumbler you could send all of the eggs into the aquarium to their eventual deaths] and the base is not stable, it wants to move/float.


A closer look. The very new eggs are white. As they get older, they will start to turn brown-orange. Then a couple of dots shows up in the brown that will eventually be eyes. Shortly thereafter a tail sticks out of the egg. The last stage looks like a tiny fish with a big ball on his belly which will get absorbed over the last couple of days.

If the eggs are still white after 3 days they are unfertilized or dead. They will start growing mold/funguses or be food for the fry that do hatch.


It's a blurry picture because the camera doesnt know what to focus on but you can see a school of fry in the middle (they came from the left tumbler). On the right side, you can see that those eggs were a a day or two behind because those fry still have egg sacks on their bellies.

Tilapia typically breed every 4-6 weeks. I found that if you strip the eggs from the mother early she doesnt seem to use all of her stored energy and she will reproduce again in closer to 2 weeks time. I think one case it was as quickly as 7 days.


Author:  tdbrueggen [ Jan 3rd, '14, 21:30 ]
Post subject:  Re: Breeding Mozambique Tilapia


Thanks so much for the detail on your system. But I guess I'm still lacking. In your opinion, or from your experience, was it difficult to get the water conditions right for them to breed? Is there any validity to what I read about the pH having to be "ideal"?

I read a bit somewhere else that said pH of 5.6 was too LOW for them to mate, and I can understand that. But does it have to be anything special or tuned, like 6.3 for example? I'm thinking with a tropical fish, the water would tend to be slightly acidic, but that's just me assuming based on no evidence.

Haha, I like Earthbound's statement, and I agree. I know they are very prolific breeders. Obviously this is why we love them! As far as I'm concerned, if I don't want to have a brood, I'll just separate male/female, or just let them eat the brood.

I did read one other thing last night, that sounded semi-cruel, but practical. It recommended trimming the upper lip of the male tilapia. There was no diagram, just a written description. It claimed it was painless for him, and healed quickly, but they said by doing this, he could no nip at the females, and their breeding stress mortality rates all but disappeared.

So what it boils down to, is at this point I'm not even sure if I have one male and one female or not. I may have a tank full of females. I won't know until they are big enough to vent. But I ready they can start breeding as young as 60 days, and as small as 2-3"...that sounds crazy! Maybe it was different strain, and not Mozambiques. I'm certain mine must be older than 60 days, although not 100% sure as I got them for free on Craigslist from a lady who didn't know much about them either. They are growing quickly (as to be expected)!

I"m really not ready to start breeding them just yet, as I don't have any place for the fry to go, so it's not urgent. I'm just trying to do my homework ahead of time so I am ready when the day comes!

Thanks again!

Author:  bcotton [ Jan 3rd, '14, 21:44 ]
Post subject:  Re: Breeding Mozambique Tilapia

Conditions do not need to be ideal, basically any temperature above 70 degrees and below the mid 90's.. sometimes it may take a temperature swing to trigger breeding habits like a raise from 70 -80 degrees.

As far as PH... You need to be reasonable and keep the fish in the PH range in which they live, grow and thrive... 5.6 is not a good ph for keeping tilapia. 6.3 sounds low too but maybe.

it may be hard to sex them so small. but here is the basic idea: male left, female right, sorry to link to another forum, but it's very relevant and not a competing forum. ... Post330600

I have dealt with aggression in a few ways without mutilating my fish. i no longer have problems with it.
1) More fish. The problem is 2 fish gaining up on one.. but if you have 7 or 8 fish the non-breeders school for protection. I have had 8 relatively large fish in the same 55 gallon tank with no casualties.
2) Add hides and break up the line of site of the tank. Make it to where fish can exist relatively close together but not actually see each other.


Author:  tdbrueggen [ Jan 3rd, '14, 22:36 ]
Post subject:  Re: Breeding Mozambique Tilapia

Thanks again Brian! I had seen those photos before and they are very helpful.

Just to be clear, I don't have my water at 5.6 or 6.3, that's just examples from other stuff I'd read (the 6.3 being completely arbitrary for the sake of an example). I don't intend to do anything fancy just yet, so I suppose my water will be about neutral.

Again, right now I only have 4 fish total, so I can't exactly overrun one male with multiple females to make him distracted. I'm leaning more on the hiding places in the tank. My wife has been working on decorating it for me. We have the standard stack of PVC pipe, and a flower pot for the nest. She's got some other random fake plants and such that are going in here and there. It makes catching the fish a PITA, but then again it can all be pulled out rather easily to open things up for ease of catching.

So like I said, I think for now I'll be leaning on merely separating the male from the females unless I am breeding. That or I need to get a few more females. But for now I'm not even sure what I have. I suppose I'll wait until these grow a little further so I can sex them, and then get an order of a pound or so from Overton, just to fill out my numbers and sexes as needed.

Thanks again for the support and simplification. I didn't think it could be that difficult with all the folks doing it, but just wanted to here someone else say it!

Author:  bcotton [ Jan 3rd, '14, 22:41 ]
Post subject:  Re: Breeding Mozambique Tilapia

Overton is where i got my tilapia too. Is there a specific reason you want tilapia? Will your system be indoors year round?

I mostly raise native fish in my outdoor system catfish, Largemouth bass, bluegill, etc. I find the temperature vulnerability of tilapia too much of a nuisance.


Author:  tdbrueggen [ Jan 3rd, '14, 23:00 ]
Post subject:  Re: Breeding Mozambique Tilapia

Yes and no. I want tilapia for the ease of breeding and prolific growth. I understand the temperature concern and will have indoor, outdoor, and a little of both. I intend to have a mating tank in the house so I can monitor them closely, and so my wife can treat them like pets. She is an avid fish keeper, so she enjoys watching them and working with them. But she can't name them all!

For my grow out tanks, I intend to have several long "raceways" built of 2x4 and plywood construction with a rubber pond liner. I'm building them such that my beehives can sit on top (see the signature :thumbleft: ). It's a whole different scheme such that crawly bee pests will fall in the tank for the fish to eat, and I gain the vertical space advantage. Understand that I am in the suburbs on 1/4 acre, so space is very valuable to me. The outdoor tanks will also be the sumps for the overall aquaponics setup that will parallel the conventional dirt garden. I hope to not heat the outdoor tanks, so they may be only seasonal use. I am in Houston, TX, so they should be good from about May-September.

For the "in between" climate, I have a small greenhouse/plant room that is currently unheated. It's not a true greenhouse, as it has a solid roof and just a few big windows on the south and west side. But on a 60 degree day it will be 80+ in there. On a summer day I've seen it break 110F in there! But the point being, I get some heat advantage, and could feasibly subsidize that heat with a small propane heater if absolutely necessary.

So what I'm thinking is a compound system, where depending on the weather, the grow out fish will be in the greenhouse or in the outdoor tanks. But as a fail safe, over the cooler months I'll always be able to keep some growing stock in the greenhouse, and actually use it as a "priming" ground so come May I already have something like 4-5" long fish that are ready to go out to the bigger tanks for their final push.

The last big catch is that my wife and I intend to move in the next few years. I don't want to put off the advantages of something like aquaponics on the grounds of "we won't be here forever" so I'm trying to design the system as flexible and mobile as possible. I've looked at IBC totes of course, but can't fit them in my greenhouse without extensive work to the door way, and they would be too tall to set beehives on top of. Still I may use them for grow out tanks outdoors if I can find the floor space for them. Speaking of vertical space, I currently have three of said IBC tanks, two of which sit atop my compost bins like water towers. But keeping the fish up there would be difficult! It really is fun tinkering around with all the intricacies of this!

Granted I haven't thought it all through 100% but have been thinking about it for a long time! I had a small setup in the past, about two years ago, with a few goldfish and two small (5 gallon tote) grow beds. It worked great for cloning tomato plants, but I got bored because the productivity wasn't enough to keep me entertained. If it can't keep me busy (and somewhat overwhelmed at times) I tend to get bored. That's why "just one" backyard beehive has become nearly 20 in just shy of two years. And why I expect I'll have a flourishing aquaponics setup in another year or so. I'm trying to learn all this stuff by doing, and certainly for the benefits of it. But most importantly learn it so I can pass it on to my own children.

Author:  bcotton [ Jan 3rd, '14, 23:06 ]
Post subject:  Re: Breeding Mozambique Tilapia

Sounds good,

You will probably be able to have your tilapia outdoors from april to the end of october in houston. I am able to do that much here in dallas. The tilapia that get the full season of growth will be big enough to harvest at that time, but i like two seaosn of growth, bigger fish. So much more meat for the work.

Tilapia do breed well but so do other fish, it's just not been documented as well. Bluegill are every bit the backbone of the food chain/prolific breeders that tilapia are.


Author:  tdbrueggen [ Jan 3rd, '14, 23:34 ]
Post subject:  Re: Breeding Mozambique Tilapia

But is the growth there on bluegill? I looked into the CNBG but read that they grow far slower, something like 6+ years to get one of decent size. So that goes back to keeping me busy and entertained.

Yeah I was being conservative on the May-September estimate. The 4 Mozambiques that I have now were obtained from a lady who had them in an outdoor setup of some sort, and she pulled them in just a few weeks ago for a cold snap. But the tank she put them in started leaking so she decided to just get rid of them altogether. I was thinking if I build the tank frames out of 2x4, then I could put 1-1.5" styrofoam insulation in the spaces to help with heat conservation as temps drop, and possible even cover a portion of the runs to prevent heat loss to the air. I also considered a solar heating loop from the grow bed sump back to the tanks. But there comes that engineer again, over-complicating things! I'd almost certainly be better off to just buy a few heaters, and pay a little more in electric each month than spending hundreds if not thousands trying to custom build all my own heating loop. :)

Do you primarily use IBC's outside or what? I saw your thread on your ferrocement system, which in of itself is a whole new concept to me.

Author:  bcotton [ Jan 3rd, '14, 23:44 ]
Post subject:  Re: Breeding Mozambique Tilapia

yes bluegill grow slower for sure. You can expect about half a lb a year, so 2 years to plate size and 3-4 for a fat BG. 6 years is close to the max age. But the tradeoff is you dont HAVE to harvest them every year and there its valuable to me to not stress and worry when a chill comes through. I am going to try to breed BG with red ear sunfish this year. The offspring are mostly male and grow larger and faster than the parents. I dont expect them to grow as fast as tilapia but maybe close the gap a bit. Overton sells a BGxgreen sunfish cross that has the same qualities.. plus it is a very attractive looking fish.

I my experience catfish grow about the same or faster than tilapia and hybrid striped bass grow a lot faster. Catfish and HSB may be difficult to reproduce though. Catfish take 3 years to mature and then due to size woudl need a large tank and a den. HSB are not the most viable reproducers for several reason i wont go into. They are not sterile, though.

I currently use IBC's but i think they are ugly. I am building out my ferro system over time and will completely convert, eventually


Author:  tdbrueggen [ Jan 4th, '14, 00:08 ]
Post subject:  Re: Breeding Mozambique Tilapia

Yeah, I just ran through your ferro thread, and posted there to annoy you as well :)

I saw the mention of the HSB, and really had not considered it. Like I said, I was looking at the tilapia for simplicity and DIY reasons. I'd rather not have to struggle to breed them, and not have to rely on "the other guy" to stock my tanks each year. Then again I might get bored with plain ol' tilapia some day and start to tinker more. I was thinking most natives need more space than tilapia, but I guess just like anything else, if the water is clean, aerated, and they are fed, a confined sedentary lifestyle for them might not be all that bad, and fatten them up a little faster. I like the picture you had of the LMB choked on the sunfish. I once caught one fishing like that, and he remained with that tail sticking out of his throat long enough for me to get him back to the house and show friends.

The IBC's are ugly, but much like your plans for Hoppes, I am lucky enough to have a neighbor with some sort of ridiculous trumpet vine that has nearly covered my tanks already. If he hand't done it, I would just plant climbing beans or any other vining plant to cover them up. The trumpet vine stays green most of the year here, so it's not like peas or beans that would die and expose the ugly tanks. Then again, I also thought about skinning the tanks out with cedar fence planks to give them the sort of look of an old west water tower. I may still do that some day to make the wife happy, and just install a sight tube so I know how full they are. I use them for rainwater storage for now.

Author:  tdbrueggen [ Jan 4th, '14, 00:14 ]
Post subject:  Re: Breeding Mozambique Tilapia

Oh, also saw you YouTube video and subscribed. Keep the good videos coming! I post a lot to YouTube as well (probably more than I should), as I've learned so much on there, I feel it's my way of giving back. I have an entire channel dedicated to honeybees (search Tom Brueggen), and then another channel on gardening and other homesteading stuff. This is where my aquaponics videos will be, channel name "tdbt3c". Oh heck, here are the links!

Honeybees: ... ASdX6UQk1g

Homesteading (aquaponics coming soon!):

I have no idea why the honeybee channel has such a weird link, but that's YouTube for you. Enjoy!

Author:  tojo [ Jan 4th, '14, 23:30 ]
Post subject:  Re: Breeding Mozambique Tilapia

Even though I do not keep tilapia nor am I planning to anytime soon, I found this thread incredibly informative and for this would like to thank you, Brian. Very good information all around.

Author:  bcotton [ Jan 9th, '14, 01:38 ]
Post subject:  Re: Breeding Mozambique Tilapia

Thank tojo, always like to hear that people find my ramblings useful. Mostly i only see the criticisms.


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