I have 5 little panda cories in a 20 gallon planted tank along with a group of celestial pearl danios. Yesterday when I fed them I noticed one pretty much turning into a torpedo. It was swimming along the front of the tank corkscrewing. I set up a QT for it, about 3 inches of water deep, put a fry net cage in a corner and put him in that so its easier to keep an eye on him. Last night he didn't move much and could only scoot himself an inch or so at a time. Did some research and since it can be a number of things I took my best bet and gave him some general cure, measured as best I could out to the 2 gallons of water he's in. Also gave him some cooked peas with the shell removed but he didn't care at all.
Today, he's been moving around a bunch more, still wiggling along the bottom but he can go 3 inches at a time now, and I just put one tiny piece of food in to test his appetite. He ate it like the good little fish he is. He's never had peas so I wanted to test with something he knew and I'll try a pea again tomorrow if he's kicking. I have both aquarium and epsom salt, but I haven't used them with him yet. Not sure if he needs it/how much/how long.
I'm hesitant to say he's doing better because I don't want to jinx it, but while I wait to see how he keeps doing, what do you guys think it could be? Swim bladder issues, if so possible causes, or something else? All that stuff.
I used R/O water that I reintroduce minerals to. Keeps my tanks pretty close in parameters.
20 gallon Tank and (QT)
Temp: 73.5 (74.1)
GH: 8 (8)
PH: 7.2 (7.2)
Ammonia: 0 (0)
Nitrate: 0 (0)
Nitrite: 0 (0)
Edit: I should add that the 20 gallon has been running for 5 months, this is the fist problem I've had with it. Figure the pandas are 6.5-7 months old since I got them as juveniles.