Iguanodectinae is a subfamily of small freshwater fish in the family Iguanodectidae. They are most prominently found in the Amazon river basin and its major tributaries, but they are also known from the Tocantins, Orinoco, and Paraguay rivers. It has two genera, Piabucus and Iguanodectes. Some species in the subfamily are taken from the wild for aquariums, like the red- and green-line lizard tetras. There is minor, but ongoing, debate regarding its taxonomy.

Iguanodectidae is a family of freshwater fish in the order Characiformes that lives in South America. It is home to the subfamily Iguanodectinae and the monotypic Bryconops clade. Several species in the family, such as the green line lizard tetra, the tailspot tetra, and the orangefin tetra, are sometimes taken as aquarium fish.