I'm resurrecting this just in case anyone has a new opinion on what could be wrong.
For the past week (maybe two weeks by now) Freddie has been extremely lethargic. It got to the point where yesterday I began floating him in a cup in his tank so he wouldn't have to swim for air.
He's eating/pooing normally but besides that all he does is lay in his tank. He looks a little bloated so I'm going to fast him today and treat him for parasites just in case he has them. From what I can tell he doesn't have them but maybe I'm overlooking them. His pellets are soaked in garlic like all my fish so I would think that would prevent him from getting parasites.
Here are some pictures..
2.5 gallons cycled (0ppm ammonia and nitrite; 5ppm nitrate)
gravel and plastic plants, no tank mates
only additive is Prime
Last water change was Sunday (9/5) and he was given fresh clean water in a critter keeper today for these pictures.
None of my other fish are sick.