What ever you do don't not feed him I believe it's his swim bladder this just happen with my 12 in red devil don't feed him change the water not to much at least 25 percent change so.he won't be in any more shock and he will be fine and add the salt like you said you would. What happen is we feed them to much because they get very greedy I used I used to feed mine at least three times I day and even though they eat it some time everything don't come out as it should. And once he get better try giving him.frozen cooked peas ever once in a while
