The Reality of Goldfish Breeding…

The butterfly fry are 4 weeks old now and I finally found time to do their first intensive cull, which strangely left me feeling simultaneously demoralized and hopeful.  In this cull I was looking for any fry with crooked backs, collapsed tail fins, or a single tail fin.  Since they’re so small yet, those are about the only culling parameters I could use.  Even so, I ended up culling out about half of the fry, which is where the “demoralized” part comes in.  One odd thing I noticed is the vast majority of fry with crooked backs actually had very nicely spread butterfly tails.  It makes me wonder if some or all of the genes controlling the butterfly tail formation in the parent fish are linked to a mutation causing crooked backs.  If so, that would be pretty unfortunate.  But I’m not sure if that’s the case, it was just a thought.

So,  I’m feeling a bit disheartened about how this batch of fry will turn out, but it’s probably too early to judge them that harshly yet.  For years I researched about goldfish breeding, so I know that with the fancy varieties, very few (if any) of the fry actually turn out as nice as the parents.  Still, it’s one thing to read about it, and a totally different thing to experience it for the first time.  I still have hope of course, thanks to a few of the fry that look to be developing very nicely.  Here are some of the best that I plucked out from the main group.  Aren’t those little tails so pretty?

12 thoughts on “The Reality of Goldfish Breeding…

  1. Jennie says:

    Yes, in most cases culls are euthanized. Sometimes older culls that are borderline are sold to local pet stores or given/sold to people as "pet" fish.

  2. Ocean Truth says:

    I'm not looking to breed fish, but I find the whole thing very interesting. Every so often I try to read alittle about it, but breeders have a language all their own. 😛 I just get lost in all the terminology and it seems as if there isn't a uniform definition with some of the terms, which just adds to the confusion for a novice like me.

    I always wondered what deformities could appear in fry. Never knew that some could be born with single tails, so that was some nice new information.

    I know it's hard to describe the ideal goldfish you are trying to breed (maybe a video idea? 🙂 ), but is Minai pretty close to it? Are there things you'd change about her to make her your ideal Butterfly?

    Sorry about the long comment. Breeding is just one of those topics I like learning about, but don't want to actually try. 🙂

  3. Jennie says:

    Hi Hayden! It would be impossible to breed goldfish without culling some of the fry unless you had unlimited space in outdoor ponds (I'm talking thousands of gallons). One goldfish spawn can have several hundred fry in it, so culling is actually beneficial because as the fry grow they get more crowded in the tank leading to poor water quality. Culling allows the healthy and desirable ones to develop properly by having enough space per fish. I will make a blog post soon that goes into more detail about culling, since a lot of people seem interested in it. 🙂

  4. Jennie says:

    That's a really good perspective OT, thanks for sharing. I also found goldfish breeding daunting at first, I had to research for years before I felt ready to even try, and there's still so much I have to learn. It's definitely a process. The book "Goldfish Breeding and Genetics" by Joseph Smartt has been a big help.

    I'll make a blog post and/or a video soon detailing my vision of the ideal butterfly telescope.

  5. Jessica P says:

    I'm sorry you had to "get rid of" so many fish. But I really can't wait to see how these babies grow! Good luck Jennie! Looking forward to more updates. xoxo
    P.s., love the Valentine tank 🙂

  6. Ricky Dillard says:

    It seems part of culling is preferential too. For example, someone decided to keep her Pinkie Bristols initially, even though they're "usually" culled. Same goes for other pinkies and matts in other fancy goldfish. I love them, yet they are not liked by many breeders.

    If you look at Raingarden's goldfish, under "Other Goldfish" you can find some that would usually be culled, but were healthy enough that they saw potential. There used to be what looked like a wakin/ranchu cross and a single tailed Ryukin that looked funky yet healthy. I think it all depends on the breeder.

    With limited space I think priorities are in order, especially as the goldies get older…
    Health > Genetic/potential health later on > aesthetics > Breeder potential.
    This is my opinion of course. In the lineup would be the questions of "If I kept the ones I don't plan to breed or sell high end, would a local pet shop take them? Do I want to spend the time setting up mass pet shop grade sells online?

    I think it might be fun to set up a class/program/workshop to educate about goldfish (bowl vs filtered tank) and give away cute ones as a completion award to those who have tanks.

    Sorry for the ramble..

  7. Mi Wang says:

    I have about 26 comet goldfish fry that I don't have the heart to go through and do an intensive cull, but there are two or three that have back deformities that are so severe that they can barely even swim, so I want to put those down. What would be the best way to do it?

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