My future army of inbreds?

Hello Yahoo community. Yesterday, I was given the privilege of seeing my friends fish tank first hand. He had informed me that he accidentally inbred a bunch of fish... 4 generations. When I saw these fish myself, I was astonished! They were brilliantly mutated, to perfection. Their backs were bent upwards and they seemed to have many problems. My friend has 10 of these fish and is willing to give them to me for free. I'm thinking of now creating an army of my new inbred fish. I will have them inbreed until they cannot inbreed anymore! I don't want 4th gen inbreeds, I was 20th gen inbreeds! Eventually I hope these inbreeds mutate into super fish. Is this cruel, or is it fine? I mean they're only fish. Thank you for your time.