For saltwater fish, the following are relevant questions that will help us, to help you with any problems you may be having. Please provide as much of this info as you can in your post.
1. How long have you had the fish? Do you know if it was wild caught, or tank raised?
2. How long has the fish been in the tank? What are the tank mates? Any aggression?
3. Is the fish eating? If so what does it eat?
4. What are the water parameters? pH, ammonia, nitrite, nitrate, SPG? What saltwater test kit are you using?
5. Is the fish showing any physical signs of disease, grain of salt size spots, discoloration, ragged fins, misting or spots on the fins, cuts, cloudy eyes, etc?
6. Is the fish "flashing" (scratching or rubbing on rocks, decorations or substrate)?
7. How is the fish acting? Is it swimming around, or just hovering in one spot or corner of the tank?
8. Did you use quarantine? If so for how long and did you have a need to treat for any ailments? Is it in qt
now? Are you currently treating with any medication(s)?
9. What size system? What type of filtration do you use? Do you have any live rock or sand?
10. Do you use any additives? Have you used any sort of meds in the main tank?
I put Qs that I thought go together to make the list only 10 questions long. Let me know if this looks good. After that, it will be by itself as a sticky.