Whats wrong with Arturo??

[Jooleeah]

I feel like i ask way to manny questions buutt...
Lately Arturo isnt doing so hot. Hes acting very lethargic and hes been hanging out at the top corner of the tank where the heater is. Normally hes a really happy guy and responds to me when im in front of the tank but for the past three days he hasnt.
Today i did a water change (i did one three days ago too) i did the de-chlorinator thing and my water reads good so theres no problem there. My tank's a 3 Gallon-er and has a heater (i usually keep the water aroune 80degrees) I recently changed the rocks because they were old and seemed kind of dirty.
Arturo eats still and he comes whenever there's food in his tank but the second hes done eating he goes back to his corner. His face has kind of lost its colour and its whiteish around the bottom of his gills (not infection/disease/fungus white (i think)) but its a silvery colour.
Whats going on :(

[Mister Sparkle]

I wouldn't rule out fungal/bacterial infection here. You may have to medicate the boy.

[xxabc]

How old is he, and exactly what are your param numbers ? Do you have a thermometer? Make sure the heater isn't going defective. What is your water change schedule ?