A Lima Shovelnose Catfish is a nice catfish that doesn't get as huge as the Tiger Shovelnose. A Pimodela Fourline Catfish would be more of a medium size catfish that if you got it more adult should get eaten by the arowana or the bass. Juruense is a nice shovelnose catfish its not nearly as expensive as the Tigrinus. Even big Raphael catfish should be able to go with those types of fish, although they hide a lot and you don't see them much. Big Synodontis catfish can be impressive and they have sharp enough spines that they should also go.