How Long Until Guppy Fry Can Be Set Free?

[Mackenzilynn]

My fish gave birth on April 20th, and the babies are growing quickly! There are three full grown guppies in the 20 gallon tank, and maybe 10-15 fry.
 
I know the official judgement of when to let fry go is when they reach a certain size. I'm not great at measuring by eye sight - so I wanted to get some opinions on the length of time until guppies are able to be let free.
 
I would imagine the fry are a half an inch big. The real question is - how big of a fish can full grown guppies eat?
 
Any experiences on this or advice would be great!

 

[snazy]

They probably can't really swallow them after a few weeks but they keep chasing them nevertheless so it depends on the tank. If there are plants, lots of hiding places, they are normally alright. But guppy fry are a bit stupid because they try eating with the adults and get chased and nipped while trying to feed. If I have to guess, depending on growth rate which can differ, a month or two the least..

 

[Mackenzilynn]

I put a little one in the big tank just to see if it would be alright. The big ones immediately tried to chase it around. I figured that would happen with any fish taht is smaller than them - so even after two months they'd be hunted.
 
The little one kept getting away, but I'd hate to stress him out. Just looking for that perfect time to integrate them.

 

[snazy]

Leave it for longer. They always start chasing them for a day, but may lose interest afterwards. At least mine do if the "fry" is too big to actually get eaten and fry are way faster too. The problem is they may not be as competitive for food but it's not always the case.
I added fry size rainbows to a tank with platies some of which are as big as 3" at least, and over 1" across. They did chase them for a while but lost interest. All the rainbows survivied.

 

[Mackenzilynn]

Not a bad idea! I have one baby who is larger than the others, he's my tester. I might plop him in there since I know hes too big to get eaten. While I don't have too many plants, there are a few places to hide. If he lasts a day I'm probably good!

 

[PrairieSunflower]

I used to put mine in (all guppy tank) after a month.  They do initially get chased but given a couple of days the adults get used to them and relax.

 

[LicianDragon]

I've been breeding guppies for about 8 years now. When I breeder trapped my fry I would isolate them for 7 days. Within that time I found they grew big enough to not be eaten by the adults. The adults still tried of course but at that age they have developed enough to easily avoid them. The development of your fry might be different though. Mine where kept at 82 F and fed 5 times daily of very tiny amounts of baby brine shrimp or micro pellet food. 
Depending on your water temps, ability to feed, and availability of hiding places, you may want to extend the length of time you keep the fry separated. I don't recommend releasing them any sooner into a tank with adults.