Is there such a thing as incest for fish?

I was woundering if breeding was the same for fish as people? i.e. mums and sons shouldn't mate or brothers and sisters. Or does it not matter?

 

it can sometime create deformity's in fish

 

I thought that might be the case.

 

I wanted to reply to this even though it has been awhile since it has been posted because inbreeding can in fact cause major issues down the line. There are 3 types of breeding to try to increase a trait or a look in a fish, first way and best is cross breeding, that is finding two completely unrelated fish that both exibit the trait and breeding them, This comes out with the strongest, hardiest fish that produce the most offspring. Next we have line-breeding that is breeding between the generations so no closer than mom-son or dad-daughter preferbly grandparents-grandkids. This produces good spawns with very few problems if any. This is an acceptable way of producing results but it is adivised to crossbreed sometimes to help bring in some fresh genes. The third way is inbreeding that is brothe/sister and this will produce the weakest fish with less fertility and risk of deformation. This is very important to know for those of you who are looking to breeding fish.