Betta Fish: Update on “Teacher’s Betta”

Hi all! I know that many of you followed and commented on my previous post
"Teacher's Betta". I wanted to give an update my original post however it won't let me edit it and for some reason it's not letting me post pictures on there either, so here I am.

"Ewww" which is what the class named him is doing very well. I upgraded him to a 3 gallon glass tank, which is fully planted, filtered and heated and even threw about 5 of my many ramshorns in there. I know I know – they need 5 gal minimum, but I have extremely limited space, so hubby is going to be hopefully building me a reinforced shelving unit for all my tanks so we can get some counter top/dresser top/TV hutch space back).

Anyway, this little guy is living his best life! You could tell that he has been neglected, because when I put him in his new tank, he immediately perked up.
If they are able to feel some semblance of emotions, I would say he is relieved and happy. Whenever he sees me, he swims right up to the glass to say “hi” with his little pectoral fins flapping like crazy. His colors are starting to brighten up and he’s already picky with his food. He absolutely REFUSES pellets since all he was fed at the school was a low quality brand. I tried to give him some Hikari but nope. All he will eat is Bug Bites and frozen brine shrimp, lol.

I do believe he has fin rot – his dorsal, tail, pelvis and ventral fins are ripped and mostly clear colored. The only fins that were spared from fin rot is his pectoral find, but they are still clear-colored. Will his fins grow back together? Can anyone give me advice on how to help them heal? I want to see my new boy in all his full-finned colorful glory! The way he was meant to be!

TL;DR: Rescued a VERY sick betta from my kiddos pre-K teacher. He was living in a one gallon cube with glass marbles for substrate, the god-forsaken SpongeBob deco, and one suction cup fake leaf. Unfiltered and unheated. Got him home, tested his water – ammonia was 8+ 😱 and "water" (if you could even call it that) was 73° F (22.8° C) and so cloudy you could barely even see a fish in there! Upgraded him to a fully planted, filtered and heated 3gal and he’s doing WAY better.