So... guppy fry...

[Martin]

I love guppies; they are beautiful and easy to keep, but yeah, they are like rabbits on steroids!  What the heck to do you do with all of them!? I know I could just keep an all-male tank, but I like to let nature take its course.  The tank can sustain them now, but I'm worried they will reach a tipping point.  Do you guys just let "survival of the fittest" keep populations in check?

[ccc24]

I don’t protect the babies after a certain point. It’s a planted tank but there are definitely fish in the aquarium that will predate on the babies and I’m ok with that. Around the time the oldest should reach the end of their natural lifespans, I’ll intervene and protect a few in a grow out tank to replenish the population if needed. Otherwise, nature is just going to take its course. 

[BrettD]

In my experience, the population can stabilize, but sometimes right on the edge of your tank's limits. I think more and more of the guppies will start eating fry more aggressively as they start feeling crowded, and females will delay egg development (or something like that). Then a generation will die, and more fry will start to show up. If you do interfere with that system by separating, do it with absolute efficiency, because you can trigger a ton of fry to drop at once. Separating can be hard because some males develop more slowly. 

I'm too lazy to go search old CoOp videos, but I feel like I remember Corey talking about this a lot. I feel like everything he has said about it has been true for my guppies. 

[Gwallace]

I don't want to step on any toes but I can think of a couple of things...

1. Your LFS may give you store credit for them if you can keep them until they get a little size on them.

2. Many people deal with culls by keeping a turtle tank or predator tank.   

On 7/3/2022 at 12:55 PM, lefty o said:

 

 

Edited July 3, 2022 by Gwallace
oops!

[PineSong]

Keeping a male-only tank has its pitfalls, too. My males were constantly harassing each other and other fish (male betta, male mollies) and the moscow guppies actually tore up each other's tails.

Letting 'nature take its course' may not prevent overpopulation, either. I have a verrry overcrowded guppy colony tank, because my ginga guppies apparently do not eat fry no matter how many there are. Or perhaps they are eating hundreds, but leaving hundreds alive, too.

Their tank is nearly standing-room-only and I am doing 50% water changes 2x per week. I've removed all the males because I can't handle the volume, but of course the ladies will continue to produce fry for many months to come. To make matters worse, because there are so many of them (I guess) it takes them forever and a day to grow, even with frozen BBS daily. I'm actually thinking of putting them outside in a tub pond just so I get can get them to grow up enough to give them to the LFS. 

I love breeding guppies and I love my little colonies but I've decided to stop the mass breeding and maybe breed one pair per year. On the other hand, there's this: