eels

big, I had one that was more than 2 feet in an aquarium, awsome fish though until he tried to eat my box fish which resulted in the death of all the aquarium inhabitance when the box fish released an uber deadly poison. Thats why I quit saltwater though, the entire filter/pump would have been unusable with out extreme cleaning and any filter media would be in the trash.

I found a website that said 24 inches in an aquarium and 39 the wild thats the max .I have one in a 55 gallon saltwater tank with a dog faced puffer.not sure his exact lenth at least a foot.

They won't get any larger than 3 feet in a tank. They're one of the smaller eels. I believe the Gymnothorax tile('freshwater snowflake') is even a tad bit smaller, but not much. I have a 'Freshwater' Snowflake in my full marine setup. He's only a little over a foot long, but he's already 3/4" tall. I'm thinking he might not end up too long, because of how he's growing so rapidly in gerth. Then again, maybe he spent part of his life next to a nuclear sub and he's going to be 20 feet long! Maybe not.