Question on "Culling"

[Vengified]

I'm not quite sure how to put this really? I have guppies, and of course, WAY too many fry! However, I am attempting to grow them out, in multiple tanks, separating sex, feeding properly, correct water quality parameters (0/0/10), etc., so I can trade them for a small bit of store credit.

I mention this, so my next question doesnt lead to responses telling me I need more tanks, I am fairly new to hobby, but not so new that I dont understand cycling (6 months with fish in tanks).

Should I be culling guppy fry fish? Based on what specifically? If so, any tips on what I can tell myself, to ease the moral burden of slaughtering infants?


An explanation of why I ask:
I am seeing some guppy fry, developing curved spines, (some 'S' shape, some tail angled upward), and the majority of them developing pintail shortly after this, and eventually find them floating or stuck in my hornwort. The mother, was completely normal, then developed a severe S curve in spine, along with dropping over 100 fry at once, and now tonight, she dropped more, just 21 days later. I have a new home for her, she is supposed to go tomorrow, but of course, now I have MORE fry.

Anyways, I'm not sure if I should "end their suffering" or cull to prevent some other poor soul the burden of genetically deficient fish, or if it is more humane to let them swim funny, get pintail, and die? I'm assuming the pintail, comes from the stress of difficult swimming, lack of food, etc, and eventually death.

ANY tips that ANYONE can offer as far as aforementioned dilemma, would be IMMENSELY appreciated! I just dont wanna feel like I'm making a bad choice either way, and that I am being humane, and becoming a model fishkeeper.

Sincerest Thanks

 

[Colin_T]

Fish that should be culled include:
fish missing fins, eyes, gill covers or part of their gill cover, bent bodies, fish that have trouble swimming.

Basically, if the fish does not look normal because it is missing bits or has a bent or twisted or deformed body (anything without a perfectly straight body), then it should be culled.

Genetic deformities can be seen when the fry are only a few weeks old. If the fry are fine for 3 or 4 months and then start changing shape, it could be an internal infection putting pressure on the spine and causing the bent back.

------------------
On to the pintail, this is usually caused by bacteria or protozoan infections. Do more water changes and bigger water changes (75%), and gravel clean the tank each day, and clean the filter regularly (every 1 or 2 weeks). And if there are no other fish in the tank add some salt. 1-2 heaped tablespoons per 20 litres. Increase it to 3-4 heaped tablespoons if no improvement after a couple of days.

The fact the fry are dying shortly after developing the pin tail would suggest a disease rather than genetic deformity.

 

[mikey11]

i have been breeding all kinds of tropical fish for over 20 years.....the first thing i tell people who want to start breeding fish is that you can not look at your fry as pets, you have to look at them as inventory, and you have to have no heart when it comes to culling, and you must cull them ruthlessly,

if your unable to do that, then breeding fish is not for you,

basically you cull any fish that doesn't look "normal"

breeding fish and raising healthy fry can be very difficult and its a long learning process, a beginner can expect to cull about 75% or greater of all fry born.....that number should gradually decrease as you learn more,

i find the most important aspect of raising healthy fry is water conditions, even more so then food.....lots of water changes in fry tanks

 

[Vengified]

Thanks you guys! The fry that I'm seeing this way @Colin_T are never more than 2 or 3 weeks old. I'm noticing the strange body shapes generally within the first week (there are SO many, I dont always see them right away), and then within the next week or two, they show signs of trouble swimming, and eventually pass on shortly thereafter. I know water quality is always suspect, but I've been checking parameters when I see this, and it's never dangerous, still showing 0/0/10-20 nitrate, and the fact that some of their siblings, and younger fry, are all apparently ok, made me think it was their genetic deformity causing issues. Also, I do 30-50% every other day in the large tank, and dont see detritus worms or other signs of a nasty tank, and use purigen as well. I do daily 10-15% in the small tank, but feed the small tank a LOT less than the large one, and avoid large water changes, because I recall seeing shrimp can be sensitive to large changes, especially after molting.

I dont doubt I have missed some dead fry, that were eaten, but I have picked out a dozen or so (in the past two months), all of which had the bent spine, either tail pointed up from halfway, or an S shape. Other than those, and whatever was eaten, I havent seen any fry that looked normal, with a pintail.

I'm not sure about if/when the fry are dead, whether they are being eaten, but I do know, with visual confirmation, that the males dont seem interested in them as food at all, in fact, my wife and I both watched Sophie (hes still hanging in there, but not as young as he once was), watched him "accidentally" swallow a fry at feeding time, then spit it out in disgust, and ran away to a corner, lol! The only guppy I have seen actively pursue the fry, is the fat black momma, and then of course the honey gourami.

Regardless of my suspicions of genetics causing the inability to feed, and exhaustion from difficulty swimming, I shall be diligent in watching for any signs of parasite/bacteria/fungus/etc. And I'm sure if I see anything out of the ordinary, I'll be bugging you @Colin_T

As for being a "fish breeder" @mikey11 it was never my intent to breed specifically, but more of a byproduct of my attempt to curb some aggression I had between males. I had one male I lost, probably to some sort of disease or something (Roney), but he was getting picked on as well. When he passed on, aggressions were turned elsewhere, so I got females, to try and direct the aggression in a more positive manner (although I guess fish rape isnt more positive). I expected average surviving broods of maybe 20-40, not broods of 100+ making it weeks in the community tank. Despite this, your advice of looking at them as "stock" at least for the fry in this purpose, does indeed help my conscience, so thank you! I do appreciate the advice! Does the standard clove oil method of euthanization still apply? I dont really wanna smash them with a hammer, nor do I wanna set that sort of violent example for my son (5 years old now, whom the fish were purchased for, as his pets).

I need to make HIM start doing all these water changes, and research, and culling, and maintenance....

Anyways, thanks to both of you!

 

[Colin_T]

I'm not sure about if/when the fry are dead, whether they are being eaten, but I do know, with visual confirmation, that the males dont seem interested in them as food at all, in fact, my wife and I both watched Sophie (hes still hanging in there, but not as young as he once was), watched him "accidentally" swallow a fry at feeding time, then spit it out in disgust, and ran away to a corner, lol! The only guppy I have seen actively pursue the fry, is the fat black momma, and then of course the honey gourami.

LOL, ah gross it moved

Big water changes and more big water changes. That's the thing to do for rearing tanks and over crowded tanks. 50-75% each day.

 

[Demeter32]

Culling fry is both a means to insure all surviving fry are of good quality and to keep fry numbers at a manageable number. Runty, odd looking and simply ugly fry are ones you should cull. No one wants to buy an ugly looking fish so better to cull it than let is sit in a pet store till it dies.

I've culled African cichlid fry but have not started culling my other species. As far as I can see, all my albino bristle nose fry are looking normal and I've yet to decide what betta fry to cull. Any fish that I do decide to cull usually end up as a snack for my African cichlids. Sometimes I really consider getting myself an Oscar to take care of the larger fry.

 

[Vengified]

Yea, I'm upping the water changes now. It also gives me a chance to try and catch a few juveniles and throw a magnifier on them and see if I can tell F/M, and if F, throw em in a jug, and drip acclimate to the other tank, try and split the load somewhat.

I wish I had more room for more tanks, I would be finding a way to cull guppy fry, as well as get the puffer I want, to "cull" the explosion of snails I have (which I know is my fault, due to the initial overfeeding to try and keep fry), but hopefully can remedy itself, by feeding less. I skipped feeding the last 2 days, and all the fish are still poop factories, and the fry are still very obviously growing. I have too much food hidden in there I guess, and the plants, and snails, and whatever else is in there. But I DO gravel vac thoroughly, every single water change. Surprised I havent had a cycle from all the vacuuming I do! Must mean my filter (Aquaclear 50, on 20g) is doing a good job, and holding BB very well?

I did grab 4 fry today too, that weren't "normal" and sent them packing. Wish I had someone to give to for food... My buddy got rid of his Oscar's Oscar's because they got too big, and he had them FOREVER! Literally had Oscar's from high school until a year ago (15 years) though I'm not sure if they were all the same, but they were big for sure!

 

[seangee]

Puffer fish eat live food. Just saying

 

[Vengified]

Puffer fish eat live food. Just saying

Yea, I know, that's why I brought it up when ranting about my snail population explosion. I am sure I could feed a puffer for at least a few weeks with the uncountable hundreds of snails in each tank! They dont like lettuce either, I tried that trick! And my fish LOVE spinach, it never lasts long enough for a snail to get a chance to creep up on it. Tried a DIY trap, caught a bunch of guppy fry, zero snails. Can't and wouldnt do copper anyways. I think that leaves me with manual removal/squish, or starve the tank?

... or I could donate any fish that my 10g couldnt support, put all the ones I kept in the 10g, and give a dwarf puffer the run of the 20g, and once he cleared out snails, throw him in the 10g, and move other fish back to 20g. Only problem being my 10g is currently growing my RCS colony, and I'm pretty sure a puffer would find those tasty too...

 

[NickAu]

Puffer fish eat live food. Just saying

So do Bumblebee Gobys, Just saying.

Both male and female Guppies will eat fry, I have seen males follow a female around eating fry as she gives birth,

 

[Colin_T]

You can use salt in guppy tanks to kill snails. 4 heaped tablespoons for 1 week and no more snails.
Or put a bottom feeding pellet in the tank after dark and then use a net to scoop the snails out when they gather on it

 

[NickAu]

Or you could build a snail trap.

 

[Vengified]

So do Bumblebee Gobys, Just saying.

Both male and female Guppies will eat fry, I have seen males follow a female around eating fry as she gives birth,

I have no doubt males and females do eat fry, I've seen many videos of it and read countless stories of it. I've seen my own females do it too. But the few guppies I have now, only one seems to eat the fry, and that's the huge bent spine female. Both her and the gourami actively hunt them too, even days after birth. But at around 2 weeks, they go nose to nose with the fry, and dont care, even if on a fasting day. And as mentioned, one of my males spit one out, which I was shocked to see!

Also, you speak of gobies eating live foods, do they enjoy snails, but NOT shrimp? Or do they get along with guppies/gourami? That's my main issue, is snails. If a puffer typically got along with my fish, I would already have one. Or if a betta, male or female got along with guppies generally, I would have probably got one of those. I've read loaches like snails, but I dont have a big enough tank for a school of them, and I've heard they like shrimp too.

So how long can I starve my tank, while being sure not to cause any harm to my adult guppies, or gourami? I have 4 juvenile guppy at 2 months, males, showing color too, and I dont really wanna lose them, but I'm more concerned about snails killing EVERYTHING, than losing a few fish. My RCS are in another tank currently, but I intend to put some back in main tank when the colony grows a bit more.

 

[Vengified]

@NickAu I tried a couple snail traps, with crustacean pellets, algaewafers, seaweed, lettuce, spinach, and cucumber, and none caught snails, but caught plenty of fry. I even tried one type I saw, using a balloon on the inlet of the bottle, so the snails could crawl in, and would sort of fall, but the balloon would fold when trying to crawl out, but none even went in, just the fry did.

@Colin_T I'll try the salt man! I hadn't read or seen that one yet! I am pretty sure we went over my stock, and it wont cause harm to any of them, but just in case: guppies and guppy fry, otocinclus catfish, honey gourami, 2 ghost shrimp. Oh, and my son HAD to have two snails, a zebra nerite, and a tiger nerite. But they are easy enough to remove if needbe.

 

[seangee]

Nerites will be fine with salt. They may even breed if yours are a male and female.