Also axolots likes to bite to invistigate. I have 3 albino and 2 wild colors. They prefer subtropical temp as they will die in cold water of where goldfish and kois can stand. They can tolerate warmer water for a short while but in the long run, they will get stress out. As for bichirs as tanks mates.... Best not to mix them. I tried before and my bichirs dismembered the legs and tail. Bichirs are somehow attracted to the amphibian scent or they knew that the fish is stress. As most predators knows a stress out animal is food. Lol! Even though the first 2 weeks was ok and the bichirs were well feed.