I agree with Rob c, but its hard do it,I bought a batch of young fish in Feb as some of you will know, there were several fish that were poor quality but I put them in a tank of their own and tried to rear them,the last one died 5 days ago,in the future I will not let sentiment get in the way as none of those fish really had any quality of life,cruel to be kind!this is something that every breeder has to be aware of.