Lions are a great fish and easy to look after, however these fish are highly poisonous and if not carefully treated these fish can hospitalise anyone from one single sting, these fish are ment to be kept in a predator tank. Eels are one of the most unique things to keep in a aquarium, with snake like features eels can climb around the tank just as a snake does in the bush. All in all these eels can be kept in any tank as long as the other tank mates aren't able to fit in its mouth.