2 month old 80 gal. tank 120 gal. system.

[Winstonv93]

So, my tank is 2 months old and my levels are great. but for some reason my 2 clowns died and my green Monti cap died as well. can someone tell me what I'm doing wrong. I feed my fish daily and twice a week i give them some frozen Mysis. I have a ton of hermit crabs and snails and an urchin that are taking care of all my algae problems. but for some reason my clowns stay up at the top of the tank in corners they aren't sticking their heads out so I'm assuming i have good gas exchange. and at night they go down and lay on the sand on their sides. this has been going on for a while and then a week ago my regular clown died and then today my photon clown died. and i just did a 20% water change. could the clowns have had a disease? I did quarantine them for a few weeks and they seemed fine. I have a green clown goby in their that I don't want to die. any advice will help.

a week ago my mom was doing something and knocked my auto feeder over and a bunch of pellets fell in. i got a lot out with the water change and my levels didn't change that drastically and nothing a water change didn't fix.

 

[Benjammin]

Welcome to R2R!

It’s a bummer to lose fish. Some people do an ICP test to understand their complete water chemistry. I would hold off on adding any more fish until your tank has matured a bit.
Some extra info would help like tank size, alk, cal, mag, temp, Saltyness, nitrates, phosphates, any corals, etc.