[7] Fishes, amphibians, reptiles, birds, and mammals fall under the Phylum Chordata which have common morphological characteristics consisting of a notochord, nerve cord, visceral clefts, and arches.

[9]  There are three infraclasses to Actinopterygii, in which Teleostei contains the majority of species and includes common fishes such as trout, salmon, flounders, and catfish.

The sucker family, Catostomidae, has populations of different species distributed globally and features similar feeding and spawning characteristics.

[3] The Rio Grande sucker is distinguished from other members of the genus Catostomus by coloration, head and body shape as well as fins and sexual differences.

[4] The head has a broad snout, ventral mouth, thick fleshy lower lip with a deep cleft on each side, and has a cartilaginous ridge of the mandible that is slightly convex.

[16] The highest flows also coincide with spring snowmelt and cooler water temperatures which demonstrate the wide range in the reproductive period, February – June, and occasionally in Autumn months.

[14] Mouth morphology dictates feeding strategies within the lower trophic level niche, and like most species within the subgenus, are largely algivorous but will predate on aquatic invertebrates early within their lifecycle.

[14] Sedimentation, competition, and flow can all negatively affect the diet of C. plebeius by depleting primary productivity and food availability.

[18] The southwestern area of the United States has historically held endemic populations in the Rio Grande River and its tributaries, but these have been substantially decreased due to land use, habitat loss, environmental degradation and non-native competition.

[17] A study conducted in Hot Creek, Colorado shows a positive correlation between low turbidity and high aquatic vegetation levels.

[18] Some studies have shown that glides and pools are the preferred habitat for the adult species and riffles may only fill the spawning life history stage.

[20] In-stream large woody debris, clean clear pools, unsorted substrates, and riffles and runs are associated with populations in the Rio Grande Basin of Colorado.

[3] Dramatic changes in the natural structure of the Rio Grande river have occurred with almost complete agricultural diversion and allocation of its average annual flow.