how to catch

several fish has started dying and i think it is brook. I got it from a mandarin i got. Of course i just plopped it in and thought everything will go fine. Well 3 fish died and now only 2 clowns and a firefish is left. The clowns are in horrible condition, still eating but skin is slouching off…...

I have a. mandarin that’s currently eating copepods and brine shrimp, nothing wrong so far, except i want to train it to eat mysis shrimp and my rockwork is very extensive… when i say extensive i mean 2/3 of my tank is rockwork. any advice on how to catch the bugger? i have a mantis shrimp tramp...