Fish aren't as cuddlely as puppies to be sure, but imagine if this op had caused the deaths of as many puppies as fish and shrimp. Do you think members would remain silent? I'm not the police. But the attitude seems, who cares they are just fish and shrimp and rather disposable. I feel when you buy an animal you make a contract with yourself to provide the best care and home. Did the op do this? That is the question everyone needs to ask themselves. As you've read, the op is kicking himself now and has likely learned a valuable lesson.
The number 10 wasn't meant as a commandment. It is a symbolic figure to keep critter population to a reasonable number.
Did I say F the fish, they're just fish after all? No.
I'm not saying he shouldn't learn and try to correct course but I also am not convince the bioload could cause a wipeout like this over night. It seems like the shrimp would have perished slowly first, then the fish. Again slowly.
This was overnight as if bleach was dumped in the water column.