- ???? Anything that moves get ate. If it's too big it gets spit back out. Anything smaller... was that sarcastic? Like Duanes said dart frogs are your best bet. In a large enough tank fly river turtles are just plain amazing they're omnivores but mostly vegetarian about the same diet as a pacu. Birds are another option- spiny monster plecos have a time share with certain parrots during the wet/dry season. Finches usually stay away from the floor- however in a mix of biotopes there's really no way to ensure the safety of the animals. That's one of the reasons why the Toledo zoo took down our rainforest exhibit iguanas and other various lizards kept falling from up high and hurting themselves (just like in the wild). The mata mata and the caiman decided live food was better. The sloth got over it's fear of people and people got scared. It's a risk that might not be worth the risk of heart break
believe it or not they have a hell of a grip and can give you a good bite if you really upset them. but mostly the concern was for the safety of the sloth