What size tank is his home? 5 gallons
What is the temp? 75-80º
What is your water changing routine? How much & how often? When did you do it last? I made the mistake of going a few weeks without changing, only adding. But today I did a major cleaning, at least 80%.
Do you use conditioner? Did you add anything in his water other then the conditioner? Yes; no.
What water source are you using? Tap (with conditioner)
Did you test his water for ammonia/nitrate/ites? If so what were the parameters? No.
What do you feed him and how much/often? Beta pellets every day, or freeze-dried bloodworms occasionally.
Any other symptoms, or has his appearance changed any? No.