maestromad said:That looks like it could be ich, hopefully someone with more experience on here can help you but start looking up on how to treat it. Heat I have found very successful. Good luck
Mumma.of.two said:It's hard to tell from the picture but is it fuzzy or flat? It kind of looks like a scale is missing. (I'm on my phone so pics aren't that great)
torres said:Ich i guess.
Ich is a protozoan disease that is often called 'white spot disease.' The scientific name for the disease is ichthyophthiriasis and the causative agent is Ichthyophthirius multifiliis. It is wide spread in all freshwater fish but appears to be more common in aquarium fish, possibly due to the closer contact and stress involved with aquarium species.
It can happen due: No Appetite, Stress, Water temperature, Water quality.
It can be treated by rising the water temperature, and using salt.
Im not an expert like alot people here are, this is just what i know because i've searched about this today.
Edit: i was writing this while you said its not ich already, sorry ;p
It's hard to tell from the picture but is it fuzzy or flat? It kind of looks like a scale is missing. (I'm on my phone so pics aren't that great)
This would be my suspicion as well especially if he is being chased or bullied a bit. I would just watch it closely & let us know if theres any change.