Fishy, angels ARE cichlids. :D Don't get tiger barbs. They nip at anything (especially flowing angel fins) unless they are in a school of like a bazillion. I'd go with the platies or swordtails. Barbs in general tend to be nippy except for possibly cherry barbs.
Matt, did you see the worms move? Only very few external parasites are visible by the naked eye and at least one of them bettas are too small to get (fish lice). That leaves velvet, ich, and anchor worms. My guess is anchor worms. Increase heat and maybe also add another tsp of salt. Some gill flukes can get large enough to be seen but in a fish the size of a betta, by then the betta has already succumbed. :/
Got two of my boys cupped in methylene blue because I don't know what else to do for them. One spends all day sitting in his plant and the other laid all day on the gravel like a rug. Other than that, fine. They eat and everything.