Hello!
He is in a medium planted 20 gallon tank, it's 2 years old, and has 0 ammonia, 0 nitrites, and 10 nitrate. I have the CO2 on for 4 hours a day. And I supplement with liquid fertilizer and have fluval stratum substrate.
He's the only gourami. 10 ember tetras, 8 kuhli loaches and some random snails.
Ph 7.2 and I can't remember about GH or kh.
2 days ago I noticed he was hiding more. And yesterday I noticed he was angled at 45 degrees or vertical near the surface of the water, and then would dart quickly around, sometimes hitting into things it looked like. So last night I set up a 2 gallon hospital tank with small air stone on gentle, small heater for a tiny tank and a lid. After 5 minutes of chasing him and having to destroy the tank plants, we caught him and put him in it.
I also put a cloth on the tank to keep him calm.
When I looked in on him this morning he was sitting on the bottom of the tank, just chilling. Just now I put in a very tiny little itty bitty pinch of dry flakes and he eventually came out and ate them. A few times he darted around the hospital tank. He does appear to be breathing hard, with (I think?) his mouth open?
No obvious swelling in the belly. And no spots or injuries I can see. The gourami is probably a year old, at least. I think I've had him for at least a year
Any ideas? After the kids nap time I could get pics of him.