What to do with extra fry?

[Taco]

Hello everyone! I purchased my first 20gal tank a few months back and stocked it with 8 guppies  and snails/shrimp. My ultimate goal for the tank was to simply have a thriving planted ecosystem and after binge watching co-op video’s I was excited for the challenge. I’ve surprised myself with how well the tank has come along, 3 weeks ago I discovered fry in the tank which seems to be the ultimate indication that you have a happy/healthy tank!
I happily purchased a 5gal for the 20ish fry because I read that other females may eat them. No big deal, right? Well, 2 days ago I had 2 more batches of fry and now have 40 to 50 fry in the main tank and about 20 in the secondary tank. After realizing I have 5 females and some quick math there seems to be many more fish in the future if I continue the trend.

Any suggestions on what to do with the fry?
I’m also wondering if separating the fry is part of the issue. Should I have a “survival of the fittest” approach and let some get eaten? Feed less often?
 

Edited November 3, 2020 by Taco

[starsman20]

Ask your lfs if they will take them. I started with 3 and have made more than 150 more in 3 months

[TheDukeAnumber1]

Keep, sell, cull, or let nature take its course in the tank which is like passive culling. IMO ideally sell them or give them to someone with a predatory fish.

[Larrimore]

Pulling the fry is definitely part of your issue.  If you pull the fry with guppies you are gonna multiply quickly.  If you don’t want to keep fighting it.  Donate the females and go all males.  Even if you separate the females, it’s too late, you’re gonna get more babies.

[RovingGinger]

I give my mutts away via Craigslist and don’t ever separate out fry from the rest of the community tank. This plan for avoiding population increases would probably work better if I were a stingier feeder, but it does well enough and I still like seeing tons of little babies around. 

[Nataku]

My suggestion is get another tank to house a predatory fish or two and all the unwanted fry go in there as food. Leaf fish are fascinating, and there many beautiful killifish that enjoy guppies  - blue gularis are one I'd certainly suggest trying. The males are stunning, and you don't need a huge tank to house them- a 20 long or a 29 will do nicely. But I realize that not everyone enjoys watching a carnivore eat. The other thought would be to give them to an LFS - be aware that unless your guppies are producing some very fine looking fish,  they will just be sold as feeders by the LFS anyhow. If you don't like that idea? Separate your females from any males,  and be prepared for a few more batches. Livebearers will hold sperm up to six months, so they'll  have several more litters drop. They'll  just get successively smaller and then eventually stop.

[Brandy]

On 11/4/2020 at 9:35 AM, Nataku said:

My suggestion is get another tank to house a predatory fish or two and all the unwanted fry go in there as food. Leaf fish are fascinating, and there many beautiful killifish that enjoy guppies  - blue gularis are one I'd certainly suggest trying. 

I wonder what is the minimum sized predator that is big enough to eat a full grown or large juvenile guppy? Like if you grew out and saved the prettiest ones, what would snack on the plain ones? Apologies if this is offensive to anyone. Just curious.

[Daniel]

14 hours ago, Brandy said:

I wonder what is the minimum sized predator that is big enough to eat a full grown or large juvenile guppy? Like if you grew out and saved the prettiest ones, what would snack on the plain ones? Apologies if this is offensive to anyone. Just curious.

I keep angelfish and guppies together. When I am typing on this forum and I hear 'popping' sounds at the water's surface in nearby aquariums it can only mean one thing. There is a gravid female guppy dropping fry and the angelfish have figured out where the fry are.

[CanadaAmanda]

You could sell them?  As others have suggested, getting a fish or two that will eat fry (a betta could also do the trick, a female is more likely to get along with everyone, but most males do too) and definitely leave the fry in the main tank.  If you see fry you're really happy with, those you may want to pull out to the secondary tank to raise up, perhaps a mix of males and females that are particularly pretty, to replace some of your current breeding stock or sell.  If your LFS won't take them, where I am there is a local facebook group and people give/sell fish there (careful, facebook's rules on selling animals are strict, so you generally have to post something like "Do you like guppies?  PM me for more info", avoid "for sale" and any prices with animals.  Folks will sell them for $1-2 each and give away or charge very little for the feeders (the ones with deformities).

[Nataku]

On 11/18/2020 at 6:19 PM, Brandy said:

I wonder what is the minimum sized predator that is big enough to eat a full grown or large juvenile guppy? Like if you grew out and saved the prettiest ones, what would snack on the plain ones? Apologies if this is offensive to anyone. Just curious.

Its a good question. Guppies gotta be culled, its just a fact of life. But we don't all have space for a huge tank to devote to something like an Oscar as our cull eater. Most ctenopoma are going to be big enough as adults to eat adult guppies- their mouths are surprisingly large. One could also keep a small group of exodons (bucktooth tetras ie mini-piranhas) in a 29 gallon. Probably 6 of them as a species only tank. They can't eat an adult guppy in a single bite but, well, they're  bucktooth tetras. It'll be bite size for them in just a second. I actually found my pictus cats were great guppy control. Threw some couple month old guppies in that tank and it wasn't the congo tetras that got them like I thought would happen.  The lights went out, still had guppies.  Came out next morning, lights came on and guppies were gone.  Pictus were fat and happy. I watched after lights out the next time - they wait until the lights have been out for a bit and the other fish slow down to sleep, then they shoot up to the surface and thrash around with their mouths open, gobbling up anything that'll fit ie guppies.

 

[Brandy]

2 hours ago, Nataku said:

Its a good question. Guppies gotta be culled, its just a fact of life. But we don't all have space for a huge tank to devote to something like an Oscar as our cull eater.

Thanks. This is practical advice. The truth is, selling cull guppies is not ethical either. I can of course euthanize with clove oil and compost them, but if something likes the free food, that appeals to me also. Pictus cats are very cool, I have loved watching your videos. I don't have space at the moment, but...life goals! 🙂

I do also have an actual cat. However, I am not sure the clove oil before feeding would be to his liking, and he would not eat them fast enough to make just dropping them in a dry dish humane. I suppose I could rinse well and see if he likes them. He is picky, lol. 

[Brandy]

Arguably, on further reflection, I think the clove oil and compost are probably the most practical. Otherwise you end up creating a bigger problem than you had before. It is one thing if you also want to keep an oscar. It is another to get an oscar purely for cull disposal. My waste not/want not mentality gets a little overboard at times. I also have hundreds of house plants and commercial compost pickup.

[ChemBob]

So in line with the sorry if this offensive part, but I just got some endlers and if I get to the point of culling / too many, would chickens eat the fish? I know they will eat insects, so curious if this could be an option as well? This would be after a humane euthanization.

[Hobbit]

I was thinking about chickens also. They very well might. I know they eat small snakes. The clove oil might put them off, and I’d want to research if clove oil would be okay for them of course. Hopefully I won’t have to euthanize a fish soon but if I do, I’ll let you know if my chickens take it.

[Nataku]

@Brandy If you are feeding culls to a cat, do NOT use clove oil! This is a poison to them. It can not be proccessed in their body and can cause liver failure. So if you'd like to feed cull fish to a cat, don't euthanize them first with clove. 

@ChemBob @Hobbit Chickens can have clove oil externally, but the effects on them internally are not something well understood yet, at least not for me.  Chickens are admittedly not something I work much with as a state veterinary inspector. I do know it is used externally (diluted in other oils like coconut and olive) to deal with mites and feather plucking. I do not know if that means they can have it internally. I know chickens will certainly eat fish, they used to stand around a water trough that horses would drink out of on a farm I visited. The trough had gambusia in it and sometimes they'd  jump out when the horses drank. The chickens were there to snap them up.

 

I am someone who is well entrenched in the 'circle of life' mentality.  Everything is eventually consumed by everything else. How to do so efficiently with as little waste and as much benefit as possible is something that interests me. Some consider this cruel, and I accept that not everyone will see eye to eye with me on this topic. But I am happy to talk about the subject with anyone who desires to. Of course, it is not my forum, so if Cory or the mods would prefer I not, simply tell me so and I can also avoid such conversations.  

I feed my culls and any deaths to my rats currently. They are not euthanized beforehand. But my rats are also extremely fast to grab any fish I provide and consume them. They really like fish. And being omnivores, it is very good for them to have a little protein in their diet. These rats later go on to become feeders for my snakes. My snake lives in a paludarium (a 220 gallon) and when he defecates that waste is used as plant fertilizer - and I have to get it out of the water quickly or the corydoras and pictus will eat part of it too. It seems to do them no harm whatsoever, but they sure make a mess of it tearing it apart, so while it doesn't seem to notably affect the water parameters, I prefer not to have rat hair floating around in the tank. So the circle of life is complete in this example. 

When I get the chance again, I'd like to have an exodon tank again. They were fascinating fish to watch. The heirarchy in a group was really neat to observe to me. I've also considered getting bichir again, they're carnivores but I don't know that they'd be fast enough to catch a guppy. Certainly big enough mouths to eat them, but the catching part is what has me wondering if they'd be a good choice for that particular purpose. Of course, I love buchir even without them having such a purpose. I always found them to be like water puppies, took to hand feeding readily. However even the smallest bichir would need a 55 gallon minimum, but preferably a 75. So that's  not a small tank.

[Brandy]

Thanks @Nataku I very much appreciate your perspective and that warning about clove oil and cats. Picky boy would have been too fussy to touch it anyway, but it is best to document this stuff because once it is free on the internet, who knows where it goes.