Dwarf puffs

[hanziie]

I have 5 dwarf puffer fish in a 60 litre tank they all seem fine except my male its like he hasnt eaten in months hes gone really skinny!
Ive also notices that around his mouth area is white! Hes swims up to the food he was even waiting for me to drop it in but he doesnt actually eat it and im pretty sure hes hungry because he acted the same way the night before i have a few photo not great ones and its hard for my phone to focus on such small things

 

[FishKeeprWanaBe]

Could be overgrown teeth which is rare but still possible with dwarf puffers. Could also have internal parasites. The next time it takes a dump see if it looks abnormal in any way