Backyard Aquaponics
A place to discuss aquaponics

I could grab my instant read meat probe and check the local water areas. Maybe we should stop worrying about the alligators and let them control the fish population. I'm about 6 miles from the Everglades. No fish kills there!

Sounds like they would have lots of food -> which means lots of alligators -> which may mean less of some other populations

Today I was cleaning the tank that I was putting all my male fish into. I bumped one of the fish and it spit out a mouthfull of something. Eggs I assume. Can you verify that these are eggs:

Yup, those are eggs. The question is: Are they fertile eggs? I find that females just go lay eggs and incubate them for a few days whenever the mood strikes them, with or without the presence of a male.

Well, I know for sure one of the fish in the tank are male. He dug a pit (moved a lot of gravel) and stays in his pot. He is also a lot larger than the others.

No idea if they are fertile, but if they are not then the male is really slacking off.. I think she spit out all of ther eggs though So, next time I guess..

sometimes the fish will return and take up the eggs when they 'calm' down.


these are eggs for sure.

I have a pair of tilapia in a 70 gallon tank together. I've got two 1 gallon pots in there for hides. I can't watch them all the time, but I'm pretty sure the female has had several batches of eggs but that the male keeps badgering her and trying to knock them out of her mouth so he can do his part again. Anyone actually observed this behavior? The male is at least twice as large as the female.

Some of the males from my first batch are looking like they might be getting close to maturity. I'm contemplating putting one of them in with my large females -- that way the female will be three or four times larger than the male. According to what I've read, larger females produce more eggs. I'm guessing the size of the male doesn't matter quite as much -- for fertilization purposes.

My wife thinks it's strange -- "isn't that, like, almost illegal? You know, so young?"

Size of the male wouldn't matter so much, but any major difference in breeder size is inviting abuse of the smaller by the larger.

Does anyone know how well keeping catfish and tilapia in the same tank would work?

TC, based on what Amacafish indicated here, it looks like the catfish would eat any juveniles in your system. So long as that wasn't a concern, they should be okay, I'm thinking. Amacafish?

According to the SRAC "Tank Culture of Tilapia" article, the optimum temperature for tilapia is 82 - 86F (28-30C), with growth falling at 68F(20C), immune system function affected at 54F (12C) and deat at 50F (10C).

What temps are folks managing to keep their tanks at? I've got about 400 gallons (1800l)in the system and 4 heaters going (which should cover about 300 gallons/1350l) and it's running 73F (23C) in the morning and 77F (25C) in the afternoons on cloudy days. On sunny days I could likely get it into the 80F's (27C+) with some solar heat as well. Unfortunately, winters around here don't generate a lot of sun.

Well, I don't know yet what summer will cause and didn't manage to get good records from the cold snaps over the winter (as system was still under construction.) I can say that my over night low air temp last night was below 57 F and the water temp about 8:30 this morning was over 70 F. I suspect that through summer, the temps will get quite warm in the system and in the winter with some protection, I expect that I can keep the water temp from dropping much below 60 F.
That is me in FL with an in ground tank (grow temp here averages 80 F through the year which is why a geo-exchange HVAC system won't work well but it might be just the thing for the AP system.)

This is sure because egg production is proportional to fish weight (for all fish) but the egg quality won't be as good as the fish gets older and older.

For catfish and tilapia mix, the important would be knowing the best fish density of each specie to keep the fish tank calm, probably more tilapia than catfish as the seconds won't be as agressive towards food as the tilapia so they will eat what falls to the bottom. Anyway for the tilapia aspect of things the best is overcrowding so that there is less territorial behaviour, and if not i'd say that the catfish would have to be bigger than the dominant tilapias or they will be losing there eyes very fast.

During the Winter mine are low to mid 70s.

My tank was down to 62 F last night and the air temp out right now is only about 63 F. I will definitely need to shut off the grow beds during the really cold snaps if I'm keeping Tilapia out there.