hes a common and about 3 inches long ive just noticed it the past cople of days and my water parms are fine i just had it tested 2 days ago and its a 10gal set up
How long have you had him? Chances are he is scraping up his own algae and feeding on leftover food from other fish. You won't always see him actively feeding.
if you want them to eat prepared foods a little trick is to just push the tablets into other foods, easy to do with courgette and cucumber etc. Feed when its light out time, thats when they feed best, at night.