Do livebearers know when not to breed?

Bombalurina

Hi guys

I have some Endlers in my 16 gallon (3 males, 8 females). The tank is overstocked by a long way, but the fish are all healthy and the water quality stays good due to extremely heavy planted and over-filtration (45 gallons worth). My pH is 6.8-7. It varies slightly as I have very soft water (1 KH, 3 GH). The Endlers are locally bred and have adapted to this water.

I know Endlers, like any livebearer, are baby machines, so why have mine not made babies? Do they know the tank is overstocked? Do they know they share the tank with fish that would eat their little ones (fat-mouthed killifish, for example)? Or are they having babies and I'm just not noticing?

Don't get me wrong, I'm not sad that they aren't breeding. I don't want babies. :p

Thanks in advance!

mattfishgeek

they probably are breeding but the fry are getting eaten before you notice. Female endlers dont gain a large amount of weight when carrying

Bombalurina

That's handy to know. Thanks! I'm just surprised none of the fry are surviving - my tank is super densely planted. Then again, my killifish can still navigate the plants with ease.