feeding

Question
I have had my tank for about 3 months and have been adding fish slowly.  I have it professionally service weekly with water changes etc.  My fish were doing fine in the morning and when I checked again at 11 am one of my 5 inch Naso Tang was stone dead.  The other naso then stopped eating and died about 3 days later.  Now my beautiful foxface has stopped eating (four days now) and I am afraid he will die.  The other fish look normal other than my gobie which is a thin as a feather.  Water condition is spot on with the exception of the Amonia which is a little high.

My other question is regarding my two clown fish.  One is a total bully and will not let the other one swim in the tank.  I have not really seen them eat in over a week.  The aggressive one is now in the pack feeding when I put in the marine algae or plankton but since he is small he only eats the minute pieces.  Should I take the abused one out?  I have had them both for about 2 weeks.

Thank you so much, I have no idea what to do.

Answer
Hey Doug,
First things first... How large is your aquarium?
Ammonia can play havoc with our aquatic pets even in small amounts. It can inhibit feeding/diet, respiration, activity and behaviors, everything. Get the ammonia down. Talk to your service and find out why your getting high levels of ammonia. Overcrowding, overfeeding, too many additions at once, etc. The ammonia will cause all of the fish to deteriorate quickly. The stress of more frequent water changes is better than the damage done by ammonia and poor water quality.
Also look at diet. What are you feeding? Is there a herbivorous supplement(algae, seaweed, etc)? All Tangs need it, as do most Goby fish.
If you have aggression and bullying between like species(a very frequent problem) unless you have a large system, where they can separate and not interact, YOU should separate them. Return one, place it in another aquarium. You'll be saving the fish. There are numerous species of clown fish, Amphirion Ocellaris, Amphirion Percula and many others, but in general ALL clown fish have an aggressive, territorial personality. So unless a mated pair, they will bully and starve like species in a system. So Id find one of them another home.
Hope this helps. Let me know if you have any more questions and how things are going. Good luck.