I'll get straight to the point as I'm quite concerned:
My half moon Betta is not well, and he seems to be getting gradually worse.
He's showing extreme signs of lethargy, tatty finnage, and on the odd occasions when he does move he darts around the tank, banging into the glass and gravel, where he eventually stays for hours without moving.
I can't see anything physically wrong (other than the fin rot, if that's what it is); there's no white spot or velvet or lumps or cuts or anything like that so I'm thinking this is something internal perhaps?
He's in a 80L aquarium, fully cycled, with bog wood and a plastic plant. Temp is 26 degrees with 0 ammonia, 0 nitrite and around 20-40 nitrate.
I've had him on a double dosage of esha 2000 to try and get the fin rot under control and try and get on top of things, but I don't think it's helped. Today I did a large water change and have started him on another standard dose as I'm not sure what else to give him?
If anyone could give their 2 cents that would be great.