iv got a zig zag eel, it's about 3" right now. iv heard they only get to about 8" max. (and yes it is a zig zag not a tire track... it's macrognathus circumcintus and not mastacembelus armatus). should the 30" of swimming room a 20L provides be enough for an adult? i dont plan on upgrading anytime soon thats why im asking.