I think the fish thing was more than animal cruelty, that was psychological child abuse as well. Smashing the aquarium then stomping a child's pet fish to death right in front of him? 2 years doesn't sound unreasonable to me.

If it's not food, an accident, or self defense (gnat/mite/ant/tick killings count as defending my home from intruders in my book) then it's just not okay.