Trouble with breeding, no fry

[Chalkbrd]

I need some ideas to check because for some reason our tilapia are just not reproducing.  We never had problems before (started with 14 and had a max of 12,000 at one time and are down to about 8,000 now), but we haven't had any babies for three or four months (which is obviously going to set us back for future sales).  The water quality is fine, there are relatively few in the tank so they have plenty of room, the water temperature has been in the 70s, feed is the same we've been feeding them.  Any ideas on what might be going wrong this time around?  I'd appreciate any ideas as to things we can check to see if they're the problem.

[Chalkbrd]

My dad informed me that he finally saw some fry in the tank today.  The only thing we can figure is that the water was in the lower 70s and now it is in the mid to upper 70s so the spawning urge finally kicked in.

[Alex Veidel]

Well, tilapia do like it warm :)

[Kenneth J Roche']

When my water temps get to upper 70s to mid 80s the gals really start to breed heavy.

[Hydroponics Curacao]

Is a water heater expensive? Mines don't breed either. Maybe I'll have to make the temperature higher. Today I saw a few fry though. Aftee many months

[Alex Veidel]

Well, it depends on how big your tank is. But, no, the heaters aren't expensive. (Although, the heating may or may not be. Like I said, depends on your setup)

I'm currently using these heaters; I like them a lot :) They come in all sizes. Get whatever works for your tank.

http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=23726

[Kenneth J Roche']

If you are seeing 'some' fry then they are breeding and most likely the fry are being eaten. I try to pull my fry 7-12days from the moms to avoid that. But sometimes I am to late, for example my biggest best female had a mouth full of 7day old brood last night. I was going to wait until tues to pull them, but they were gone this morning presumably eaten by the other 6 females and 1 male.

[Chalkbrd]

I'm wondering if that is part of the problem as well, that some of them are being eaten.  Normally my dad does scoop them out when he can see them (he figures by the time they get big enough for him to see, they are big enough to be moved).

We live in northern Indiana so over the winter the brood stock was kept upstairs in a tank (the warmest part of the building since heat rises), but I think the water might have been a little too cool (low 70s) for them to reproduce.  It's kind of odd because that's the same tank he always kept them in and they had no problems getting him from the original 14 to the 12,000 he had before he started selling them on a regular basis.  Last summer when the weather got warmer, he transferred them to an outside cement tank (about 17' in diameter) and, since we had 90s and 100s most of the summer, there were tons of fry.  This summer hasn't started out nearly as warm so the water is just now warming up to about 78.

I've tried doing research online for him, but most of what I find says, "Oh, it's really easy to breed tilapia."  LOL  I started asking him all the things I could find that might affect the spawning, but from his responses, it sounded like he had all the bases covered.  He said when he put the females in, a couple of them appeared to be pretty plump at the time, but that was a few months ago and he never did see any fry resulting from that.  With them outside now, he's able to have water plants floating on the surface so the fry can hide in their roots (and often do).

Normally he sees large groups of them like in the hundreds, but the ones I saw the other day were in groups of more like 10-20.  Very different.

Maybe as the summer progresses, they'll get more in the swing of things and we'll be able to build things back up again, but I'm afraid down the line he's going to have a few months with no sales because of this glitch in the supply chain.

Maybe we just need to pipe in some nice romantic music for those long winter nights next year.  lol 

Btw, during the winter they don't heat the water, they heat the building.  It reduces the humidity in there (not totally, of course, but significantly) and the building was previously used for other purposes and already had a heating system.

Kenneth J Roche' said:

If you are seeing 'some' fry then they are breeding and most likely the fry are being eaten. I try to pull my fry 7-12days from the moms to avoid that. But sometimes I am to late, for example my biggest best female had a mouth full of 7day old brood last night. I was going to wait until tues to pull them, but they were gone this morning presumably eaten by the other 6 females and 1 male.

[Jeff S]

Will the mother eat the fry if left in a separate tank with them?

Kenneth J Roche' said:

If you are seeing 'some' fry then they are breeding and most likely the fry are being eaten. I try to pull my fry 7-12days from the moms to avoid that. But sometimes I am to late, for example my biggest best female had a mouth full of 7day old brood last night. I was going to wait until tues to pull them, but they were gone this morning presumably eaten by the other 6 females and 1 male.