I've been spending about four months cleaning and airing out a tank that got infected with TB from an ill guppy (I no longer buy fish at the petstore I got it from). I've bleached and rebleached and rinsed and air-dried this tank many times, and now I've set it up with plants, gravel, a new filter, etc.
So now I need some cheap, easy-keepers to test the tank to make sure it is free of TB before I put my betta into it. I was going to try fathead minnows sold as feeders, but after a quick search I found that all of the local feeder fish for sale are infested with parasites (yuck).
So now I want your opinions on what the best betta-compatible test fish would be. I was going to go with neon tetras, but do you guys have other ideas?