yeah, it's kinda like dogs. Sure some people like mutts but they are worthless, pure breds are where you see pure blood. You can breed a pure bred and a mutt and it's still a mutt. The only difference is that in fish you can get all kinds of mutations and then theres always the people who just "free willy" but hey.....
Well basically with hybrid fish, if you breed two hybrids that looks the same..doesn't mean the fry will look like the adults. They aren't pure strains therefore you are likely to end up with alot of fry with undesirable characteristics and no one will want them because they want fish they can breed and know what's gonna come out.