when to release platy fry into community tank

[venzi]

So after a year of struggling, my platies finally gave birth about 2 months ago.  I've managed to save a a dozen (surprisingly over the course of several weeks) and they're doing well in a breeder box so far.  I know that I should be giving them a bigger tank to really grow, but I don't really care to grow them that fast nor that big.  I'd actually prefer to breed smaller sized platies if I could.   Anwyays,  so the biggest fry is about 0.5 inch.  I'm pretty confident it wont fit inside any of the other fish in my community tank (they're just platies and female bettas), but can anyone give some advice if its still too early to release the 0.5inch fry into community tank?

For some reference, the 0.5 inch fry still can't swallow 0.5mm pellets.  Also, I noticed today at least 4 other smaller fry (less than 0.5inch) surviving in the community tank somehow.  I'm pretty amazed there's still survivors after all this time.

[TheSwissAquarist]

Half an inch is ok, but I’d leave it a bit longer if you’re worried. 

[beastie]

With a smaller mouth fish (mountain minnow) I released when the fry was 1/3 of the parents and it was ok , maybe that helps

[mynameisnobody]

@venzi what’s the size of the aquarium? Is it planted? 

[venzi]

On 9/19/2023 at 4:21 PM, mynameisnobody said:

@venzi what’s the size of the aquarium? Is it planted? 

20g and yes planted.  I have a few fake plants in there as well that give pretty good hiding spots.

[AllFishNoBrakes]

The best answer I can give probably won’t be the answer you want to hear, and you’ve already kind of mentioned it in your original post, but as long as they don’t fit in the mouths of the other fish you should be fine. 
 

If there are other fry in the community tank surviving, and the fry you’re worried about are bigger than those, then you’re probably okay. Make sure everyone is well fed and you should be fine. 

[venzi]

On 9/19/2023 at 8:27 PM, AllFishNoBrakes said:

The best answer I can give probably won’t be the answer you want to hear, and you’ve already kind of mentioned it in your original post, but as long as they don’t fit in the mouths of the other fish you should be fine. 
 

If there are other fry in the community tank surviving, and the fry you’re worried about are bigger than those, then you’re probably okay. Make sure everyone is well fed and you should be fine. 

So regarding that rule of thumb of "fitting inside the mouth",  would a bigger fish try to "chew" or bite off like half the fish?  Or would they pretty much want to swallow them whole?  So like the head of the fry is the widest part, but the tail is skinnier.  So if a bigger fish were chasing the fry around, they could theoretically easily stick up to half of the fish up to the head perhaps, but then realize "oh the heads too big for me to swallow".  Would they at this point just release the fish or try to bite off half the fish? My intuition is that they'd spit the fish out (with perhaps some damage to the fry) b/c that's the typical behavior I see when fish try to swallow a food pellet too big.

I was also thinking some of these fry now have that orangish color kicking in  (since they're red wag tail platies).  So if that coloration is a sign of maturity, then at that point, would the adult platies realize they're the same species and not want to eat their own kind?

[AllFishNoBrakes]

Fish will typically eat anything that will fit in their mouths. As long as it won’t fit, they probably won’t try to eat it. Obviously not a scientific and specific answer, but that’s the best one I can give. 
 

If I was you, I’d leave the fry in the breeder box and watch the ones in the community tank. If the ones already in the tank are surviving the ones in the breeder box should be fine. Making sure everyone is well fed should help curb them from needing to try to take on a big meal from being hungry. 

[mynameisnobody]

Agreed with @AllFishNoBrakes, I’ve honestly never come across someone that wasn’t over run with fry a year into owning platies. What’s your feeding regimen? 

[AllFishNoBrakes]

On 9/19/2023 at 10:50 PM, mynameisnobody said:

I’ve honestly never come across someone that wasn’t over run with fry a year into owning platies.

Agreed! Platies were some of the first fish I ever had, and for the life of me I couldn’t figure out why I wasn’t getting fry. Then, it finally happened and I was so stoked!

Then, I got a different color, and was feeding baby brine shrimp daily and then BOOM!! I was very quickly overrun and overwhelmed and had to make some changes, lol. Baby brine shrimp and live bearers can be a dangerous combination. 

[venzi]

Yea I think my problem was that initial female platy I had just wasn't healthy at all to give birth.  These latest female platies I added a few months ago seem to be healthy and giving birth no problem.

As a quick update.  I released the half inch fry into the community tank last night without issues so far.  I was pretty convinced that if these other smaller fry were doing just fine then it would be fine as well.  Seems like the bigger fish think it's food until it gets closer and realizes it's a bit too big and then just stops.  So that's good.

It's pretty cool to see these small fry scavenging around the gravel.  Definitely brings more life to my tank.

Thanks for all your feedback.