Just about everyone that sells predatory fish has little Bowfin at the moment. It's gonna take a while to grow up, but a juvenile is the way to go if you ask me. The posts before me in your thread gave most all of the names of the vendors here that have them for sale. IMHO, they don't have any if all in the way of color difference's. If you keep them on a light color substrate, you generally have a lighter color fish. Same with darker gravel or whatever, you have a darker fish. They are just attempting to blend in like most all predatory fish. They can be kinda hard to get to thrive in an aquarium setting sometimes. They like aged water. I usually use a little more declorinator and try to fill a couple of buckets up with water so it can sit for a while. After 24 hours, the chlorine evaporates out but I still use declorinator. Just out of habit I suppose. Good luck.