From sores and lethargic behavior to overnight swelling and floating on his side

[MADxMAC771]

Ira had developed a sore on the side of his head that is still present, and was also exhibiting lethargic behavior. His appetite was regular and was being fed a total of 5 pellets daily at 2 different feeding times roughly 8 am then again around 8-9 pm.

After 4-5 days of antibacterial treatment for the sore that looked infected, he had his old rigor back and was energetically swimming around his tank. This morning when I left for work he was fine. Today at 430 when I returned home he was floating on his side and I feared the worst. When i approached his tank he swam abruptly toward me and leveled out for a moment only to pause and float to his side again. This is clearly some sort of SBD or constipation. He seems bloated at the moment, but he did not seem that way this morning.

What can I do?

I have daphnia in the freezer and i was thinking of going to get some aquarium salt to do a 10 minute salt bath to help clear him out. Also I was going to switch from my kordon antibacterial to betafix.