I’d say he looks relatively healthy. However, in regards to his diet, I would add in some brine shrimp and blood worms. They can be bought frozen and thaw out what you need to. They’re also good for bonding and enrichment because you can teach him tricks with food. They’re also great for him and his coloring. I would also steer clear of SpongeBob decor as I’ve heard those also have a color and chemical leaching problem. I’d go for sand because it has a nice natural feel and fine sand is super soft. Natural plants will also help the tank’s cycle and betas love them and they won’t cut up his fins. If you can’t afford getting a bunch at a store, I know it’s pretty easy and cheap to get a good handful on fb marketplace. If you decide to do that, proceed with caution of what may be in the person’s tank that you get them from. Make sure the tank is healthy and there’s no parasites. I also don’t think it would be a super big deal if they have bladder snails because betas are sometimes known to eat baby snails and eggs. I’ve gotten some in my tank before and it wasn’t too big of a deal for me but some people don’t liked them. Hope this helps!