First off I want to thank everyone
for their help and careful responses. It is so great to have a board who is dedicated and knowledgable. YOU GUYS ROCK :D
He is still eating and acting just fine, the little warrior...
While it looks like his caudal fin may be on the mend, Ernesto's anal fin split from bottom to body today....
. Like I posted before, I did 2 big changes yesterday and added a pinch of salt. I also added a light filter.
When I saw the fin had split (he was fine when i left for class this AM, and when I said hi to him when I got back, it was split), I immediately called PetCo and spoke to the manager, who was their fish guy.
What he said was this:
I was doing way too much. It was the water changes and the addition of the filter that effectively punched him like Mike Tyson. His advice was to leave him alone ('cept for feeding), turn off the heater (when i looked, it had skyrocketed to 83 degrees F!!!), and see how he does over the next 48 hours. I promptly took the nano heater out, and will see what he does on room air (usually keeps at about 75 or so).
Now do I feel terrible!!!
As an academic, I research things pretty thoroughly and I take everything into consideration. As a fish keeper, I only want the best for my fishy friend.
Let's hope all is ok soon.