Hello folks - you have helped me greatly in the past, so I am returning a few years later with a different fish. Little Mars is acting very lethargic today and I cannot pin-point what is going on. I found him resting on a leaf at the top of his tank today, gasping for air. He is not interested in food, and, when gently touched, floated to the bottom of the tank like a dead fish. I have attached a couple pics of him after I scooped him and put him back on top of a leaf against the surface. It seems like swimming is very hard, so being against the surface for air is ideal. 

Some other Tank info:

\- 7 gallon long, with cherry shrimp tank mates and an assassin snail.

\- 78degF water, 7.6 pH, 0 ammonia, 0 nitrite, 0-5ppm nitrate (just measured)

\- Heavily planted tank with almond leaves. Shrimp seem healthy and are swimming as usual. 

  
He eats betta bio-gold pellets with occasional frozen bloodworms. He does scavenge occasional detritus worms from the floating plants (little white worms that probably came from our lfs). 

I should also note, he has had diamond eyes since we got him. There is a chance I cannot determine what popeye looks like against what diamond eye looks like. One eye (facing the camera) does seem slightly larger than the other. It also looks like some slight pineconing just above his nose to his dorsal fin.

Betta fish is lethargic... any advice appreciated.