latley my fish have been dieing for no reason I recently bought new fish and 1 crab my crab died along with one of my new fish withing 2days of me buying them shortly after one of my older fish died! I have a fish that I'm not sure of its name it is clear and a bit like an eil I want to know what it is and if its causing my other fish 2 die! the fish that died was my angelfish and another clear fish of the same kind! ???