it's really 2 possible reasons:
a: territorial matters
b: scared of other fish
it is called carnibalism
Is vibrating
Use 3 shakes of fisk flakes(food)
it mean the fish that was bumped into is going to died unless you pour cooking oil in the tank and lick up the water like a little doggy
to have more important things to do
Cowboys loved a colorful phrase! This meant not so good, as in "no great shakes." It can also mean just a few minutes, as in "Give me a few shakes to get ready." Also, it can mean a good opportunity or chance, as in "He gave me a fair shake on that land."
When your fish has a bloody fin, it means that it is either getting scraped by an unknown source in the tank, or, if there are other fish, that another fish is hurting the injured fish.
He scared.
they are silenly saying your an idiot
You are doing well
It will be done soon
If you mean to go fishing rather than another word for a fish then angling is the term. An angler is a fisherman (or woman).