I believe they are fish. I think looking online concerning their natural environment would be helpful. I think they like to be able to walk out of the water, or at least be in very shallow water. I would have them in a semi-terrestrial environment where you could (if you're into plants) have maybe ferns, moss, sundews and venus fly traps, etc in the background, or maybe you could have a muddy area with mud from a natural source. I would do my homework, and maybe bake the mud to kill unwanted organisms, or not. They might be better with sand in an aquarium because it's easier to keep clean. They're very cool fish and I was thinking of getting them myself someday.