problems withtilapia breeding set and egg mortality

[shadowrunner762]

Greetings all,

I am having a issue with the breeding set for my Tilapia. The set consists of 1 male to 4 females, the water parameters are excellent, and the food is at the desired rate for the size of the fish. the fish are not stressed, and eat like they have never seen food before.

The problem is that although they display the mating rituals, i have yet to actually see the act in progress. the last 3 spawns i have caught the females with eggs in there mouth were from 2 fish, and i have missed the event by up to 5 hours. the eggs in each case will be circulated in her mouth and then within 24-36 hours, purged from the female.

I have not attempted to transfer the female or interact with them at all, and am not sure if it is the male not doing his part, ( which i swapped out the male last spawn thinking i had an issue) or there is something else i am missing...

any thoughts on this would be appreciated
thanks

[kellenw]

Hey Shadowrunner,

It could be an infertile male, but since you've now tried two, that's not terribly likely... though still possible. It could also be that the females are collecting eggs prior to the male fertilizing them. This happens somewhat frequently with younger breeders, but they tend to get better as they mature. The 24-36 hour window where they seem to spit them or swallow them is pretty consistent with behavior associated with females brooding non-viable eggs. Honestly, they probably just need a little time to figure things out.

[qommunity]

I would greatly appreciate knowing about what works (or doesnt).

I have a similar problem in my own (start) attempts at breeding. To date, I have had 4 females keep eggs in their mouths, only to have them just disappear. The latest female nursed the eggs for about 7 days (up to last night), then this morning the eggs were gone and the female starting to eat up the duckweed floating around in her tank.

I havent considered switching males yet, and am just about to try and DIY an egg tumbler (tomorrow)

[shadowrunner762]

hey guys,

sounds like i might have some un-educated fish LOL!!
ill let them have a month or so to figure things out, but at the end of it i will rotate another male in to see if i had just a dry spell.

I seem to remember a post some were about getting the females on a scync. spawning cycle, by putting them in the dark for a certain amount of time, but for the life of me i cant find it. ( it may of not been here, it was over a yr ago i remember seeing it) anyone know what i am talking about? if i can sync the fish it might help with keeping track of what is going on.

thx

[kellenw]

The post/thread you're talking about is here somewhere (I wrote it... hehe). I'll try to dig it up tonight if someone doesn't beat me to it.

[GreenFin]

Hey Kellen, this is as good a spot as any to ask: At what age/size do tilapia stop (or at least mostly stop) cannibalistically eating fry?

The literature I find online is not helpful, since it just says young tilapia are cannibalistic and adults for the most part aren't. That's woefully imprecise.

So when exactly do tilapia tend to grow out of the cannibalistic phase? Is it when they're 3" long? 4"? 6"? 8"? 10"?

(Assume we're talking about an environment with a lot of other food available.)

[kellenw]

Well, technically they will always take an easy meal if they can get it. However, they are extremely cannibalistic until about 3 or so inches.

[shadowrunner762]

hey all,
am still having issues with egg mortality, the last batch lasted 36hrs and then were gone by this morning.
i have been going over the possible problems, and the only thing i can think of is possibly that there is to much water movement in the cage. do the breeders need a relatively calm area to spawn in ? i cant think of anything else that would be the issue. i am at 6 spawnings now without a viable batch and 2 differant males.

be safe all

[Pugo]

I have them breeding in my tank, and wish they would stop. But I have a great deal of water movement it hasn't upset my fish or even slowed them down on the breeding side of things..

[mopa]

if the females reckon that there is little hope for the young ie crowded tank, other females could eat young, aggressive male, not enough space etc. they will eat the eggs instead sometimes. Could also be high bacteria count or fungus in water infecting eggs, and females swallow dead eggs . maybe try uv steriliser?