I think Albert might be ill
His left gill opens more than his right and appears to be inflamed, and his eye looks a little bloodshot (can't tell if that's just the photograph though).
There's also some white on his top fin at the base, but I can't tell if that's some kind of fungus or if it's a colour change...
He still has his appetite, but seems to be resting on plants or on the bottom of the tank more often than he did.
He's in a 4 gallon tank with a filter and heater (set to 26c), I've been doing 15-20% or so water changes every other day.
I've been feeding him a combination of Tetrabetta and frozen Daphnia.
Would appreciate some expert eyes. I've marked the areas I'm concerned about. Oh, he might look a bit plump, had to bribe him with food to get him in photographic range.
Marks are on the outside of the tank, could do with a wipe!