They are all small tetras, none longer than 5 inches, and often have attractive silvery or striped scales, which makes them a target for the ornamental fish industry.

Members of Iguanodectes are relatively slender, shaped somewhat like minnows; ichthyologists Carl H. Eigenmann and James Erwin Böhlke both compared them to smelt in general body composition.

[2] When Iguanodectes is compared to the genus Piabucus, the other member of the subfamily Iguanodectinae, the pectoral fins are shorter and the chest is not as deep.

[2] In all Iguanodectes, the maxilla bears a set of multicuspid incisor teeth that are flared out at the tip and contracted at the base.

[11] In 1909, ichthyologist Carl H. Eigenmann proposed Iguanodectinae as a subfamily, which was solely home to Iguanodectes at the time.

[19][20] Cope's placement of the species into a new genus was later accepted, but it adopted the specific epithet given by Günther.

[14] However, research by Oliviera et al. in 2011 prompted authorities to move Iguanodectinae and Bryconops to Iguanodectidae, which had been revived from Eigenmann's work.

[22] As a fairly new taxon, Iguanodectinae is not listed in several databases; sources such as NCBI and the Interim Register of Marine and Nonmarine Genera consider it synonymous with Iguanodectidae,[23][24] where Eschmeyer's Catalog of Fishes and GBIF simply don't acknowledge it, uniting all three genera in Iguanodectidae.

[10][30] Though their ecology has not been studied extensively, captive specimens demonstrate a poor tolerance for adverse water conditions.