Betta Fish: Betta!!!

So I got him the second of september. His fins was mishaped but I still liked him alot. I had seen him in the store 2 weeks earlier while getting plants to my new aquarium that was cycling. I was really really thrilled to se him still in the store when I got back. The 3 first pictures are from the very first day. Petstore said to feed him on day 3. I did and he ate a half lil pellet. The fourth day he ate nothing. I bought the same food that he had been feed with at the store. I read that they can become depressed and sad. The Twelfth september I bought two amano shrimps. He did not care about them and one shrimp even relaxed at the same leaf as him. The fourth pic is of my aquarium that day. I bought blood worms to him also, I told the staff at petstore that he hasn't eaten since the fifth september and they were really concerned. He did take one bloodworm but spit it out. I know his stomach is tiny so even if he didn't eat it all, some of it must have stayed in his belly.
The 17 sept he still hasn't eaten since that bloodworm on the 12. I thought he was really really depressed and sad so I thought hmmh Imma buy him some guppy's. At the store they told me to change my sand, so I did. I bought some more green to him too. Still…sad…fish … The 24 september came, still no food. His food all over the floor of the tank, I thought. Corydoras pygme!(( I had planned for them from the beginning to join my aquarium)) I went to the store and had water from my tank, I had pictures, I showed the worker the sixth picture. He asked me " is that fish still alive ? " I started to laugh because me myself had no idea how he could still be alive. I did not laugh because I was happy. I was sad and still is sad. I had taken bloodworms and tried feeding him with tweezers, I had been staring at the aquarium for hours per day, I know bloodworm only once a week so I had tried feeding him with it twice since I bought it. Given him his original pellet food every day. I even shut of the light for 2 days. I shut of the pump some hours per day in the beginning (( on the fifth day)) . I modified the pump a billion times to not make the water crazy flowing. Anyway, the staff told me that his " skin " I don't know the word for it. Was like a tiny bit like dropsy and I couldn't see it and still can't. He said he had a weird body, skinny in the middle. Something wrong. He said he had a parasite and that's why he did not eat. He said this fish will die and when he said that he could se me just breaking inside. I haven't even named my fish yet because I think he will be dead every morning. I started asking about medicin. He said it mostly to late but you can try salt water treatment. Fish is weak and it's 50/50 he will die during the treatment… I got home, fixed everything up, lots of salt in little water (( new water and from aquarium )). Fish will stay there 1-1,5 minutes, until he's on the brink of death. I put him in. It was really intense seconds !!!!!!!!! After 1 minute and 19 seconds I could see him trying to breath harder so I took him up and put him back. He was still alive !!!!!!!! After two hours I tried feeding him with pellets, no reaction. I have video of him seeing the food then swimming away. So I decided I wait until tomorrow. This morning I tried with pellets, nothing. Nada. About an hour ago I took some blood worms and put in the tank… One by one I drop them in, seeing them drift down to the bottom of the aquarium, fish is swimming towards it but still did not eat it. I try with another and another…. I think the fifth bloodworm HE TAKES AND DO NOT SPIT OUT!!!! THEN HE TAKES ANOTHER!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!;;! THE FISH HAS EATEN FOOD FOR REAL!!!!!!!!!!

Also the white red dot on his fins, I was told it was nothing to worry about. Today, he looks like this (( not even 24 h later )) 7 picture. I have no clue about anything I'm just very happy that he has eaten. I REGRET NOTHING!!! I WOULD DO IT AGAIN IF I COULD. Two bonus pics !!!

I know theres a formula to answer, I see what I can remember.

Aquarium size : 8 gallons
Temperature: 24-25 Celsius
Citizens : one Betta fish, 3 corydoras pygme, 2 amomo shrimpies.

IM JUST A HAPPY FISH OWNER TODAY 🤘😭