Betta Fish: Update on abandoned betta

First, thank you all for your advice, it’s truly been invaluable. I had an empty 16.5 liter tub, so I used that as his temporary home. I washed it out with hot water and a brand new sponge so there wouldn’t be any soap residue. I used the substrate and plants from the original jar. I have him sitting on top of my seed starting heat mat which heats between 70-80° F, and I thought bringing the temp up slowly might be easier on him. I didn’t see the comments about seachem prime until after I got back from the store, but I did get their neutral regulator which still detoxifies ammonia, and also softens hard water. I’m hoping this will be ok for the time being. I got him new food which he seems to like much more. He has a great appetite, and he’s already learned to swim up to my hand when I drop the pellets in for him. I’m dropping them in one at a time, and I give him 2-4 (depending on the size) a few times a day. Tomorrow I’ll be getting the testing kit everyone recommended, a filter and proper heater, and I’ll take a look at the tanks petco has on sale.

He seems like he’s doing well. He’s alternating between being very active and exploring and resting. I think he’s tiring himself out because he’s not used to having so much space. He likes to rest on his lotus as well as hide under it, and he’s been hanging out in the little ceramic pot I gave him. The tub has a bit of a reflection because it’s not completely transparent, so he’s occasionally been trying to fight his reflection.

My cats are fascinated with him, and he seems to be equally as interested in them. Sushi has decided he likes sleeping on top of the warm tub, but don’t worry, I drilled holes in the lid so the little guy won’t suffocate.

Thank you once again, I’m truly appreciative of all of the kind words and advice.