Philosophical Question on Culling

[Goosedub]

Hey,

My wife and I were having a discussion. I currently have Endlers breeding in a 20L tank. I really like them. Anyway, the only other tank inhabitant is a BN Pleco. Eventually that endler population is going to go nuts and be unmanageable. I said eventually I will need to add a fish to help eat the fry. I spoke to my wife previously about culling fish and euthanizing fish with clove oil, which seems pretty humane. My wife wondered why not just get rid of the extra fish that way. She kind of has a point.
 

Yes, I know, It would be preferable to offload them on a LFS, but take that out of the equation. I have seen a lot of people add fish to their livebearer tanks to help control population. Is that any more humane than euthanizing them? Would you rather be eaten or put to sleep?
 

The conditions in my tank are far more hospitable than nature, which allows these fish to breed out of control if left unchecked. It’s just a weird philosophical question and I am wondering what everyone else’s thoughts are.

[GardenStateGoldfish]

Id rather have the chance of escaping death (prey option) then clove oil, 100% chance of death. Having a fish passively pick off fish is the better option, your strongest fish will survive and your weakest will be eaten.

 

Besides, as someone who also struggles with culling, there is a big difference for you between killing them or something else killing them. You actively clove oiling them, will feel terrible.

[lefty o]

it really is a personal decision. pick the least objectionable method to you.

[Mmiller2001]

Life feeds on life. Plus, those that survive encourage better genetics.

[ccurtis]

I think I agree with the others. Clove oil is good in a pinch for a sick fish that you would not want your other fish eating, but when it comes to culling, I tend to think natural selection is the best way. You are letting nature take its course. 
 

I have a tank with shrimp in it. It has a honey gourami and some small tetras as well. They tend to keep the population under control. The ones I do cull out go into another tank with larger tetras, rams, and other bigger community fish. If they live, good on them they can stay, but if the other fish get them, the fish has a healthy snack and nature did it’s thing.  

[H.K.Luterman]

It all comes down to what you're ok with, as the others have said. I personally only use clove oil to euthanize a fish who is obviously on its way out. I leave any dead fish I find out in the woods, which the local raccoons and other wildlife appreciate. However, fish that I euthanize with clove oil don't seem to ever get eaten; I guess the smell and taste is bad. 

And so I use predator fish for population control, because in my opinion, fish killed with clove oil are just wasted. I mean I guess they do go back into the earth at some point, but *shrugs*... it's just how I feel. It's a touchy subject, especially for us animal lovers. 

[FlyingFishKeeper]

Hi, it’s a personal question for everyone, but for me at least I would use other fish. That way someone is “benefitting” from the death of another fish in the form of a meal rather than just having dead fish.

[Goosedub]

I’m getting the general consensus here is with a  fish, which is my preferred option also. Another question:

 

Are there any fish that don’t require a heater but will also fit in a 20 L and eat endler fry?

[Brandy]

what is your temperature range? a surprising number of fish will eat fry, including other livebearers.  A couple of golden wonder killifish would do the job I suspect. 

[Goosedub]

Just now, Brandy said:

what is your temperature range? a surprising number of fish will eat fry, including other livebearers.  A couple of golden wonder killifish would do the job I suspect. 

Well, so far I haven’t seen anything below 73. It is spring though and may dip more during the winter. I guess I can always add a heater, I just don’t want to. I love the look of the golden wonder killifish. My concern was that it’s mouth could possibly be big enough to eat adult endlers.

[Brandy]

1 minute ago, Goosedub said:

Well, so far I haven’t seen anything below 73. It is spring though and may dip more during the winter. I guess I can always add a heater, I just don’t want to. I love the look of the golden wonder killifish. My concern was that it’s mouth could possibly be big enough to eat adult endlers.

It could. the temperature works though. The endlers might self regulate, or you could maybe add an apistogramma. I think any larger carnivorous fish will likely eat fry, the key is finding one that likes your temperature. 

[Alexa]

I would rather feed my culls to another fish so their life isn’t “wasted” but... I accidentally started a guppy colony in my flowerhorn tank this way... so. 🤷‍♀️ 

[CalmedByFish]

I've been thinking about this a lot lately, so I'm glad somebody brought up the topic.

Almost a decade ago, I let my guppies breed to the point that I couldn't keep up with their water quality. Over time, I had hundreds get sick and die younger than they should've. I was even trying to keep boys and girls separate. It would've been more humane to cull, but I didn't understand that at the time.

A few years ago, I had the same problem after buying a single molly that was forever having fry. With my life being too difficult to handle them, I did my research to find a species of fish that I would definitely enjoy, definitely eat fry, and live a fairly long time. I bought 1 angelfish to put in with the mollies, and that solved it. 

Now, I draw the line at "gulp, gone." If a fish will vanish in a non-gruesome gulp, that's fine. But I don't want a fish to be torn up, or relentlessly chased around, being terrified. I'm okay with a fry obliviously swimming and then *gulp* it's gone. 

[Stash Beardsley]

I personally would rather give healthy fish away for free if you cant sell them. Or use them for food. I do cull sick fish though. I personally use a razor blade knife. If I suspect dropsy or columnaris I just cull.

[Brandy]

21 hours ago, CalmedByFish said:

I've been thinking about this a lot lately, so I'm glad somebody brought up the topic.

Almost a decade ago, I let my guppies breed to the point that I couldn't keep up with their water quality. Over time, I had hundreds get sick and die younger than they should've. I was even trying to keep boys and girls separate. It would've been more humane to cull, but I didn't understand that at the time.

A few years ago, I had the same problem after buying a single molly that was forever having fry. With my life being too difficult to handle them, I did my research to find a species of fish that I would definitely enjoy, definitely eat fry, and live a fairly long time. I bought 1 angelfish to put in with the mollies, and that solved it. 

Now, I draw the line at "gulp, gone." If a fish will vanish in a non-gruesome gulp, that's fine. But I don't want a fish to be torn up, or relentlessly chased around, being terrified. I'm okay with a fry obliviously swimming and then *gulp* it's gone. 

I *might* have elecric blue acaras for this reason. 🙂 I am fortunate in that I can let my fry get to the half grown stage and they are still gulp--gone if I put them with the acaras. This lets me cull on lack of color, but does make it a more deliberate decision, which some people might be uncomfortable with.

[Kirsten]

Killifish, a larger livebearer like a swordtail, I bet even some barbs would do the trick in cooler water. I've put a single angelfish in each of my 36g livebearer tanks and even thought they're still pretty small, they're endlessly chasing fry around. I love my livebearers, but I'm cheering for the angelfish! I haven't tried it, but some people recommend dwarf african frogs for eating anything they can catch. Don't know what their temps are, though.

But, really, it won't get out of hand if you feed sparingly, keep an eye on it and have the time and patience to catch up a few dozen every month or two to give away. Leave the killing for dangerous genetic problems or terrible illnesses.

[CalmedByFish]

2 hours ago, Brandy said:

 I am fortunate in that I can let my fry get to the half grown stage and they are still gulp--gone if I put them with the acaras. This lets me cull on lack of color, but does make it a more deliberate decision, which some people might be uncomfortable with.

If that was the only way I could keep my breeding fish, I can imagine doing it. 

This will take the convo to a whole new level, but: I would intentionally net out and cull fish with genetic problems before they had a chance to breed... while all of my children have special needs. Animals and humans are 100% different in value. I have come to have no qualms about my opposite stances between animals and humans, but I do think about it. I mean... how could you not in my position, right? 

[Brandy]

3 minutes ago, CalmedByFish said:

If that was the only way I could keep my breeding fish, I can imagine doing it. 

This will take the convo to a whole new level, but: I would intentionally net out and cull fish with genetic problems before they had a chance to breed... while all of my children have special needs. Animals and humans are 100% different in value. I have come to have no qualms about my opposite stances between animals and humans, but I do think about it. I mean... how could you not in my position, right? 

If we stop struggling with these things it is time to stop raising animals in any capacity. Short lives should be good lives, as any farmer knows. There should only be one bad day. 

[CalmedByFish]

2 hours ago, Brandy said:

If we stop struggling with these things it is time to stop raising animals in any capacity. Short lives should be good lives, as any farmer knows. There should only be one bad day. 

Well said. 

[Fish Folk]

There is something to wrestle through for every serious aquarist here -- particularly those of us who enjoy breeding fish. It is important to think ahead about this. If we are not equipped to raise, care for, and move along spawn from our fish, we should probably be cautious about actively propagating them.

Livebearers, like Endlers and Guppies, are a particular challenge because of how prolific they are. Convict Cichlids can also produce an unbelievable number of fry. We do keep some medium / larger fish -- African Cichlids, Electric Blue Acaras, etc -- that will reconstitute protein. But the best plan is to have a place that will be glad to take the fish and sell them. We are fortunate to have several very generous LFS that will exchange either store credit or cash for fish. If you've got friends with Kids, sometimes it's exciting for them to get some of your leftovers. If I recall correctly, this is how Master-breeder Dean Tweedle got into keeping fish -- we was paid for some work did for a family neighbor / friend in _fish_ (which he temporarily kept in a toilet until some suitable container was found). We've given away a lot of fish to friends, and to children of family friends.

I think that one very good thing to do is to join a Fish Club / Aquarium Society that offers an auction at monthly meetings. We've found that is an excellent way to move stock along (pre-COVID). 

 

 

[tonyjuliano]

Paradise fish can live easily in cold water, and will eat anything that fits in their mouths (while also being beautiful).

Count me among the “let nature take its course” crowd.  If I have the euthanize, it’s because of illness, and can best be done with a quick dip in carbonated water, IMO.

Edited May 12, 2021 by tonyjuliano

[Sunshinebluemoon]

I have a Betta in every aquarium that I have live bearers in. I never thought about it as population control but I guess it kind of is. I just love bettas and I love building community aquariums for them. I never thought of it as culling. Now I guess I do. I don't think it's a bad thing.

[Kirsten]

12 hours ago, CalmedByFish said:

If that was the only way I could keep my breeding fish, I can imagine doing it. 

This will take the convo to a whole new level, but: I would intentionally net out and cull fish with genetic problems before they had a chance to breed... while all of my children have special needs. Animals and humans are 100% different in value. I have come to have no qualms about my opposite stances between animals and humans, but I do think about it. I mean... how could you not in my position, right? 

For me, it's really about quality of life for the fish and keeping the community of fish in my aquarium happy and healthy for many generations.

Luckily, my fry all seem to be vigorous lil buggers so I haven't had the experience of culling them, personally, but let me use a sad example from a sheep farm I worked at:

Some kinds of sheep have a terrible recessive gene where their eyelids tend to curl inwards. Their eyelashes scratch the sheep's eyeballs and they get infected, which can kill a young lamb painfully or at the very least blind them, making it easy for them to be outcompeted for food, get bullied or lost from the herd, basically the saddest possible life for a sheep.

When you see a lamb with curly eyelids, you have to act pretty fast, popping the eyelid back into position, sometimes using aids like tape or more drastic means to try to keep them from curling under again, castrate any males from the batch, and make sure the ram who sired them (the likely culprit) and his daughters never breed again. It's hard to treat, so, often, after several attempts to help correct their eyelids have failed, the lambs are usually sent to market before they can get worse. The ram in question can live out his life separate from the ladies, if you can manage it, or can get sold if the shepherd doesn't want to keep paying to feed and house him.

The treatments for this are not often successful and are stressful and sometimes painful for the sheep. Far better, all around, to keep those terrible genes out of your flock in the first place.

In a community fish aquarium, you have much less control over who breeds, when, and illnesses are even harder to treat and identify. Unlike humans, who have loving communities of caregivers to help and treat anyone with disabilities and who have a good chance of living long, happy lives, fish with problems often live in misery and can pass on those problems to their young. As the human who put them in this situation, I think we have a responsibility to the fish to give them the best life and minimize any stress or suffering.

[Tanked]

 

Is there something that you can change to make their environment less conducive to breeding?  My Barbs have been known to eat their smaller roommates.

[CalmedByFish]

I just remembered something that I don't think anyone's mentioned.

Part of what pushed me into "my fish can eat my fish" was just reading the ingredient list on their flake food one day, and wondering how exactly the fish in the flake food went from swimming to unconscious. It was probably a horrible experience for them. Probably not anything quick or humane about it.

From thinking about that, staring at the ingredient list, I realized whatever happens in our home aquariums is usually far less awful. 

Now that I think about it, it may actually be more ethical to feed our carnivorous fish in a way that keeps us in charge of how the food-fish are treated throughout their life and death. Not practical really - but getting closer to ideal.