What is it? Fish health isn't static. It's hard to tell if a fish is alright from pictures without any further description unless it's a lesion, sore, or it's externally apparent. Is it behaving in a way that would make you worry? Did you quarantine? How long have you had the fish? Also, it's sometimes important to you know....include the species of fish you got.
I'm guessing it's an ebj, how long have you had it? How big is the tank it's in? What's it with?