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Last year, I bred Harlequin rasboras and 50% of the fry had tail deformities. I recently found out why; the adult female had a double-crook tail deformity that I never noticed before. Almost all of the deformed died soon after, probably from difficulty swimming and finding food. One fry had such a deformed tail that it could only manage to swim in spirals, which was kind of funny to watch. It died.

Also last year, two tail-deformed guppies (brother and sister) bred and half the fry also had deformities. One fry came out with a balloon-shaped body like a balloon Molly and was grotesquely ugly. I recently decided to cull (using an ice bath) the deformed fish, including the parents. I thought this was best to prevent any future breeding and passing of this trait.

I didn’t feel bad during the culling, which was sort of fascinating to watch. However, after the deed was done, I did start to feel bad. None of the fish were in poor health and except for the crooks in their tails, were perfectly fine. For the males, you could barely notice due to their large finnage.

This raises some ethical questions:
1. Is it ethical to allow deformed fish to breed?
2a. Is it ethical to cull the fish with deformities?
2b. Is it ethical to cull deformed fish when they are in good health?

I didn’t ice all of the deformed guppies. I still have one because I wasn’t sure it was a deformity at the time. But I’m considering culling this fish as well.
 

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Need to select best looking male and female for breeding, look closely for deformities.
Inbreeding (brother/sister,fish from same batch of fry) is more likely to result in more deformities,fewer fry born with each successive batch.
Every now and then introduce new male or female to prevent afore mentioned.
I have bred as many as three generation's to get the one male/female I like,,then select a new male or female not from same batch of current fish.
Is good chance that fishes we buy from store tank's are all from the same hatch,so I sometimes purchase new fish from different source.
Nothing wrong with euthanizing poor specimen's but maybe better to take measures to prevent the need??
 

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Selectively inbreeding and culling are what give us our beautiful fish from the start.
If breeders did not, today, our only choices in bettas would be veil tailed, and guppies would all look like feeders.

If one chooses to breed, they should select healthy stock from the get-go, and something that will be a joy to look at in future generations.
If one is looking just for a pet or something to fill the tank, takes pity on a deformed but otherwise charming fish, they should pass on females and choose only males if species permits (like guppies).

Best is to get something you enjoy looking at, and pass on the deformed, so not to keep the cycle going, and prevent future guilt trips on yourself about culling. Let others deal with it, unless you are serious about breeding, because there's always going to be a deformed/inferior one somewhere along the line. Guppies are "the million fish" :)

-Stef*
 

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Inbreeding,crossbreeding ,in my view/opinion produces weaker specimen's,fishes with unpredictable physiological problem's,unpredictable behaivor's and physical characteristic's,lower fry survival rates,and weaker fish overall.
What once used to be considered fairly hearty species capable of adapting to wider range of condition's,is increasingly becoming an oddity rather than the norm.
My two cent's.
 

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It's the one aspect of the hobby I detest, but there's really no way to get around it. A while back I bought a mated pair of angels. Their first batch looked good at first at the sub-pea size. They also threw a 50/50 mix of plats/gold and black. However, almost all of the black ones were missing an anal fin; altogether. The biggest cull I've ever done, and it just wasn't fun; but had to be done.

Sometimes there can be grey areas to this question. I think there is some leeway in determining what defect is truly "wrong" and should be culled. I keep a 180G in the den that's pretty much reserved for the "wrong" fish. Fish that have nothing more than a kinked ventral, but are otherwise awesome specimens; tank bullies that need to go to fishy boot camp, larger specimens that have given up on the breeding aspect of fish life; etc. etc. It also allows me to be somewhat sentimental with some fish. So odd pairings will form in that tank, and in a 180G there's enough room in there for nature to guide things along in relative calm. The best example is beautifully colored male blue paraiba marbled male and a drab paraiba female with a kinked ventral. The male came from a batch that at a tiny size looked like they would be blushers. Wrong; gillplate holes. This guy was the survivor of the bunch and the hole closed to about 2MM at best. The blue in him is just really nice so these two spawn about every two weeks and the others just give them space and that's that. Knowing their genetic issues, I just can't trust what their offspring would hold for future generations.

Then there's the defects that some purists among the breeders of certain species just consider "wrong". There have been several incidents of angels bearing ventrals that have so many rays that they appear to be dragging mops. I doubt you'll see many of those in LFS any time soon. I thought they looked pretty cool. Who decides?

Then there's the intentional "defects". I'm not one for any of the various "balloon" fish. But somehow, we all see more and more examples. Who decides?

I suppose just about all of us will agree that defects that don't allow a fish to develop, swim or eat properly should be culled. If we didn't do it, they wouldn't have survived to the stage where the defect would've been noticeable in nature. The grey areas? Not such a cut and dry thing if you ask me.
 

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Inbreeding of healthy hardy stock does not produce weak or compromised fish.
There are small ponds jam packed with inbred wild sail fin mollies.
Generations upon generations, with no new blood.
Although, any deformed ones will be naturally culled before they even leave fry stage.

It's when something is "hot" and bred to death without culling or a plan, just to get them on the market with a high dollar price tag is where things go wrong.

-Stef*
 

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Inbreeding of healthy hardy stock does not produce weak or compromised fish.
There are small ponds jam packed with inbred wild sail fin mollies.
Generations upon generations, with no new blood.
Although, any deformed ones will be naturally culled before they even leave fry stage.

It's when something is "hot" and bred to death without culling or a plan, just to get them on the market with a high dollar price tag is where things go wrong.

-Stef*
We shall have to agree to disagree I fear;)
Your opinion carry's no more ,no less weight than mine.
Just my observation's over the last forty year's in the hobby.
 

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We shall have to agree to disagree I fear;)
Your opinion carry's no more ,no less weight than mine.
Just my observation's over the last forty year's in the hobby.
Well, I like to hear the opinion of those experienced :)
We can agree to disagree.
A lot of what breeders breed for is what judges at the show place high.
I see it in persian cats-the face got so extreme, the poor things could not breathe properly, and I do agree with your point on other animals, but without cross breeding horses and donkeys, we would have no mules-the best of both animals, although sterile.

When I was young, I gave my Dad 3 guppies. (2 girls and a boy) 10 years later, he still had them jam packed in a 10 gallon, 1/2 filled with mulm, no plants, it was disgusting. Fed Hartz Mt.
There had to be over 100 in there-bent up and gimped like gnarled branches, some actually sickle-shaped, yet they still thrived.
I took them from him when I got my first apartment because they had sentimental value, separated boys from girls, gave some away, and they slowly passed about 2 years later. I would not repeat that, but some inbreeding is important, not saying breed to death. Although, my Dads guppies didn't follow that rule.
I outline my breedings and plan everything in advance.
Health is always the first trait I want to instill. (updated my Rorschach thread)

-Stef*
 

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Discussion Starter · #9 ·
There's an emotional attachment to the fish that I've raised since birth. It seems wrong to kill it just because of an aesthetic problem that doesn't even cause any difficulty swimming or eating.

The two fancy goldfish I have (redcap orandas) both have tail deformities. The 6-year-old is almost human and has emotional reactions to being lonely. He got depressed and stopped swimming so I bought him a $2.50 friend of the same variety. This immediately perked up his mood and he behaved exactly like a person would to finally seeing someone after years of isolation. But with only one friend, he still longs for more. I don't want him to breed because he would just pass on the same defect so he'll probably live out the rest of his life never fertilizing eggs.

How do you feel after culling a large number of fish? I feel bad looking at their lifeless, cold-blooded bodies so I throw them in the compost bin where they would mold and decompose.
 

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In fish, inbreeding isn't necessarily a problem unless you started with bad genes to begin with.
In mammals, it's an different story since it's much more complex.

An example are those dessert pup fish that lives in little cave pools in the dessert. They've been going at it for hundreds or thousands of years.
 

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I have no issue with culling in principle. Especially with such prolific species where in the wild deformed fish typically would not survive long. Don't find it fun to do, though.

Just thought I'd throw in the discussion that some deformities will not be genetic, but rather developmental issues or injuries. Why not breed a fish with some rare and desirable traits who happens to have a tail kink that came from its egg being squished at the bottom of a pile? etc.

Of course - differentiating between such issues becomes extrordinarily difficult when you start getting into epigenetics... which we still are only barely scratching the surface of understanding. IE what about the kinked spine that was caused by a lack of some trace element in the water during embryonic development interfering with calcium being processed correctly in that one area along the animal's spine? (I totally just made that up, but it could be an example.)

As far as inbreeding goes- this debate gets held 8 million times a day on 8 million different forums, I'm sure.

My own opinion is that linebreeding can be done responsibly, but responsible linebreeding involves periodic incorporation of fresh blood. Populations that are so isolated and linebred that all individuals are incredibly genetically similar are at incredibly more at risk for extinction events than populations showing more genetic diversity.

This has been researched and documented over and over and over again.
 

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Selectively inbreeding and culling are what give us our beautiful fish from the start. If breeders did not, today, our only choices in bettas would be veil tailed...
Not true, should instead read, "If breeders did not, today, our only choices in bettas would be the wild form, not even veil tailed would have been produced."

Inbreeding,crossbreeding ,in my view/opinion produces weaker specimen's,fishes with unpredictable physiological problem's,unpredictable behaivor's and physical characteristic's,lower fry survival rates,and weaker fish overall.
What once used to be considered fairly hearty species capable of adapting to wider range of condition's,is increasingly becoming an oddity rather than the norm. My two cent's.
That's also my $0.02 ... do I hear $0.96 more?

...Then there's the intentional "defects". I'm not one for any of the various "balloon" fish. But somehow, we all see more and more examples. Who decides? I suppose just about all of us will agree that defects that don't allow a fish to develop, swim or eat properly should be culled...
What about "the intentional defects" which "don't allow a fish to develop, swim or eat" as efficiently as it would without such defects?

Inbreeding of healthy hardy stock does not produce weak or compromised fish. There are small ponds jam packed with inbred wild sail fin mollies...
...those dessert pup fish that lives in little cave pools in the dessert. They've been going at it for hundreds or thousands of years.
Those "small ponds jam packed with inbred wild sail fin mollies" and "those dessert pup fish that lives in little cave pools in the dessert [which have] been going at it for hundreds or thousands of years" are the result of: survival of the fittest, Darwinian evolutionary theory, natural selection, reproductive success, and the survival of the form that will leave the most copies of itself in successive generations, as opposed to a domestic product which is the result of aesthetic qualities which command the highest market value.
 

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Culling is on of those things that needs to happen, and is important to the hobby. Culling replicates natural selection that happens in wild habitats/ecosystems. However in cases like yours op, if your happy to keep the deformed fish in non breeding situations, and the fish can live happily without any negative effects. You don't really need to kill the fish. You can let them live out their lives in your tanks.
 

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I often see people make this mistake with livebearers. People go to the LFS and select some males and females of the same strain, not keeping in mind, that all the fish in that tank are probably siblings.
Having made that mistake myself with a few fish, I have to admit that deformities were as high as 25% in their offspring. We are talking very good looking fish here (show quality if you wish, with all the horrible things people do to produce those fish).Now I make sure to get fish 2 or 3 months apart if I want a pair.
 

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Kind of off topic-
I had a molly fry that had a crooked spine/tail and his head was much bigger than tail. He was way smaller than the other fry and swam slowly and wobbly. I kept him with the other male molly fry. The biggest made sure to drive everyone away to let the deformed "sprinkle" eat.

Sprinkle remained very small and deformed for 4-5 months. Then it was like overnight he suddenly grew very fast and became a proportional, regular black molly. I was so fascinated. I wonder if it had to do with taking his brothers away, or just a strange thing. Is that normal?

If I'd have culled him, I would not have witnessed this transformation. But, why would someone want to have a bunch of deformed fish around? Unless you don't mind, like me.
 

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Well, if culling is not performed, and line breeding,cross breeding,or inbreeding continues over month's with no new blood,then undesireable trait's that may have already been in gene pool will occur more frequently in the fry,thus weakening successive generation's.
Is what I believe is happening with more frequency.
Fish farm's more concerned with turning profit's $$ than producing stronger strain's.
 

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Tomorrow is culling day again, I try and do it while the fry are small enough to be one bite.
 

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I don't believe culling is unethical. Being we are raising fish in boxes, often with exemplary care, nature certainly won't do it for us. Sometimes a fish has deformities, sometimes they just aren't the product you want, and sometimes you just don't have the room for undesireables. It's up to the fish keeper to decide.
 
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