eating fish

Some people eat shark fish is it haram or halal in islam

I have a 26 gallon cichlid fish tank. I am looking to buy more fish. So far I have 2 red blood parrot fish, 1 black knife fish, and 2 snails. I know I can't have many fish since cichlids are territorial, but what fish would you recommend to buy? Thanks!

I am a non vegetarian, but whenever I eat fish now, my stomach hurts. What could be the reason for it and remedy thereof?

I got a fish tank and evrything was good and my fish were having fish, and I just added water to the fish tank and just 2 days ago I notes that every time that I check my fish tank there are a lot of fish dead I want to know why?

"i have 2 small red haeded gold fishes from 20 days one fish is a bit smaller than the other.sometimes the big one chase the smaller. The smaller one yesterday eat the food and throw it out several times. Today she do not want to eat. I separate it in another bowel and put dry flakes every hour...