Before I begin, I want to set up a kind of disclaimer - I have zero interest in breeding fish for myself. I don't want to take risks, and frankly, I don't have enough time and money to maintain a fry or condition the breeding pair.
However, I'm very interested in the methods of breeding - I know there has to be more than one tried-and-true method. I'm also wondering about genetic diseases or physical traits that are considered "undesirable." If you can, do you back-breed the parents?
Is there any concerns that arise from breeding siblings or other relatives?
Is there any good, informative links where I can look up more on my own?
I'm also a horse person, and there are inherent risks with each breed. For example certain Quarter Horses suffer from a paralytic genetic disorder called HYPP. Horses lose all control of their muscles and go into a HYPP attack, when they basically have a seizure.
Now, somehow connecting horses to fish, are there risks of genetic disorders associated with each type of fish?
(I think I'm so interested in all this because I'm a biology major and breed Daphnia for science experiments!)
Undesireable traits can sometimes vary by who your talking to. A good example would be the rose tail trait. Many people think rose tails are pretty but a lot of people don't think they should be bred because of the genetic issues going on behind the scenes so to speak.
Generally the most common undesireable traits are bent spines, short bodies, narrow dorsals, thin fins and weak rays, not enough ray branching, lack of full spread (when talking about HMs),uneven or missing scales, swim bladder issues, and any other obvious deformities.
Breeding sib to sib and father/daughter mother/son is common but should be done with caution as too much inbreeding can begin to cause highly undesirable traits. A breeder I know found out that too much in breeding caused his fish to begin to loose ventral fins or develop two ventral fins on one side etc, (other deformities can become present as well).
Betta splendens are all the same species so there's not really any one disease that one betta gets over another like HYPP in QHs but to go along with your analogy I guess you could say that some lines throw more defects than others. These would be lines that are severely inbred or just fish that shouldn't be bred in the first place.
This is all awesome information. Thanks! I just spent the last 45 minutes reading about this. There was a lot I actually didn't know about betta genetics, so it was really cool to learn about the dominant/recessive traits.
Is there a way to see if a fish is aggressive by, say, his color? Back when I kept four bettas at home, we had an albino danio with each betta. The only danios that got injured or killed were the ones housed with the red bettas (typically, we couldn't get them out in time). Ever since then, we've never put a danio in with our reds (and we haven't gotten new bettas at home in two years, since a disease of some sort wiped out the entire tank twice).
I'm not really sure. Most breeders want aggressive fish (i.e. ones that flare) especially to show and sell, however too much aggression is a bad thing (because the fish won't breed). So some breeders tend to like nicer fish, some meaner.
Personally I want to see a male that flares and builds nests but knows how to treat a female right and a female who is respectful of the male.
In my own spawn right now I'm seeing some fry (both males and females) that are quite aggressive and some that are very timid. Both parents were very.. um.. confident? They were pretty peaceful when breeding so I wouldn't want to call them aggressive but they also did not back down from each other or other fish. It leads me to believe that temperament has to be really bred for.
There are fighting plakats that are hugely aggressive, so much so that they must be kept from other fish entirely. They've been selectively bred not for color or finnage but for aggression for hundreds of years so in that case it is safe to say that temperament will be passed down and any non-aggressive fry will be culled to keep that trait strong.
Most show/popular betta types (VT, HM, CT, PK, etc) are being bred for type and not temperament so it's very wishy washy.
I hope I'm not muddying the waters.. gotta run off to class now but I'll try to write more when I get back. If you didn't know I'm a total genetics nerd :p
Ha, it's okay! If becoming a zookeeper doesn't work out, I really want to go into animal genetics. So it's super great that I have someone else to talk to about this and learn some more on my own.
As you said, aggression is desired. However, is it possible to breed for aggression but not an inclination to fight? I know that's as easy as saying that you can breed out the inclination of pit bulls locking their jaws when they bite, but that idea is pretty much near impossible to execute.