Bert's Mystery Swim Bladder Ailment - Help!

[CMatt]

Hello everyone!

This is my first time posting, though I have been searching the forums for almost a year and you guys have been amazing so far! However, my little Bertie has come down with something that I cannot figure figure out. Apologies for the long post that follows!


His history...

I've had Bert for 9 months or so and I suspect he is fairly old since he seems to have no end to problems. I have already treated him for finrot and a slime coat problem and he's a bit of a tailbiter. He lives alone in a filtered 5 gallon tank (though, I may move him to his original 1.75 gal tank since I don't think he likes the space and that may be the source of his tail biting). I do not have a heater for the tank because I find having the light on for 14 hours a day is sufficient. Currently the water parameters are normal and stable and I do a 50% water change every week. I feed him a diet of flake food twice a day with the occasional blood worm as some variety. Despite the finrot when I first got him and the slime coat problem when he moved tanks, I am sure that the system I have going works well for me as I have not had any other issues with any of my other fish in the same tank conditions.


The problem

For the past week or so Bert's health has been decreasing rapidly to where he now has a swollen belly and just floats on his side on the surface of the water, usually behind the filter outflow. Occasionally, he wiggles himself down to the bottom and sits under a leaf or decoration which holds him down.
I originally was absolutely sure that he had SBD because of his bloat and the fact that he was having difficulties coming down from the surface of the water. I immediately began fasting him and began 100% water changes with an epsom salt treatment. However he still began rapidly declining and I ruled out SBD in favour of perhaps an internal parasite, though I am still not really sold on that.
I began feeding him again yesterday and was encouraged to see him excitedly (as excited as a dying fish can be, I guess) flop (he no longer swims, he flops) himself across the surface and eat up every morsel of food. This morning he pooped normally - also encouraging. Now don't freak out but also last night, at the encouragement of my veterinarian (who also happens to be my father), I gently massaged his bloated belly and swim bladder. Now, my father is a small animal vet and admittedly knows about as much as I do when it comes to fish, but I think Bert did look a little better afterwards and this morning.
This morning, though I found him behind the filter outflow again, he swam to me and was a little more graceful and upright in his movements. Even though he's looking a little brighter, I am still not convinced he's out of the woods. What do you all think?? Apologies again for my wordiness

Also, I will try to upload pictures later when I get home from campus.

[Nasha66]

I would advise that you put his food beneath the surface of the water to prevent him from gulping to much air which will only worsen his condition