If you are at the point to where your other fish's life is in danger, consider moving them to different tanks.
its unlikely you can stop a fish from eating another fish without taking that fish that's being eaten out of the fish tank.
Probably. As long as being abusive "works" for him (lets him get on with his normal life) there's really no strong reason for him to stop.
You cannot stop him from being abusive. He needs to be in counseling and have somebody (other than you) hold him accountable preferably a neutral party. People that have survived living in abusive homes are in survival mode, right now is not a good time to be in a relationship with him. Although he may in fact be a sweet person inside, the abuse will eventually trump all rationality and sweetness within him and you cannot help him with this, you can encourage him to go to counseling but there is nothing you can say or do that will help him.
Unlegally- run away from home or tell your mom to stop being abusive Legally- you can move out when you are 18. It's legal!!! Good luck.
find a better person emional abuse never stops
Separate them in the tank by placing a glass partition between them. It is the males that fight.
call 911 if you are being abused or are abusive and can't stop either call 911 or a counsellor to help you.
Fishing nets don't really cause any damage, other than to the fish that are being caught.
The separation of powers.
put them in a separate tank
I recommend eating the fish.
Tell them to stop and if they don't then refuse to communicate with them till they do.