Firstly, well done Oklahoma!
On the issue of killing the fish, i watched a programme the other week about a very endangered species of tiger. The guys had some of them in captivity and when the male approached the age that he would start to be sexually active, they neutered him. Why?
You would think that they would do exactly the opposite and encourage breeding, and they do, but only with the purest strains of the species. As this guy was cross bred somewhere down the line with another species of tiger, he was no good.
Letting this guy breed wouldn't save the endangered species, but create a hybrid species all of it's own.
My point is, maybe it's the same with the dyed fish. They can't take the chance of letting them breed, just in case we end up with sub-strains of dyed fish. Lets face it, they won't have much chance of producing prize specimen offspring.
I agree with the euthanasia, but think the guys who are doing the dying should be strung up.