Temporal range: Oligocene–Recent 
Eigenmann & Eigenmann, 1918
The family Pimelodidae has undergone much revision. Currently, it contains about 30 genera and about 90 recognized and known but unnamed species. Wikipedia lists 109 species in this family. The low-eye catfish (previously family Hypophthalmidae), and thus the genus Hypophthalmus, which contains four species, was reclassified with the pimelodids.
This family previously included fish that are now classified under Pseudopimelodidae (previously subfamily Pseudopimelodinae) and Heptapteridae (previously subfamily Rhamdiinae). This family also previously included Conorhynchos conirostris, currently incertae sedis. However, a molecular analysis has shown unequivocal support for monophyly of the individual families and the genus Conorhynchos into a clade called Pimelodoidea, including Pimelodidae + Pseudopimelodidae and Heptapteridae + Conorhynchos.
The six main groups within Pimelodidae are Steindachneridion, the Phractocephalus-Leiarius group, the Pimelodus group, the Calophysus group, Zungaro, and the Sorubim group. The Pimelodus group includes Pimelodus, Exallodontus, Duopalatinus, Cheirocerus, Iheringichthys, Bergiaria, Bagropsis, Parapimelodus, Platysilurus, Platystomatichthys, and Propimelodus. The Calophysus group includes the five genera Aguarunichthys, Pimelodina, Calophysus, Luciopimelodus, and Pinirampus.
Many long-whiskered catfishes grow to be very large, including the piraiba, Brachyplatystoma filamentosum, reaching about 3 m in length. They have three pairs of barbels, with maxillary barbels that may reach the length of the fish's body. Like many other catfishes, their bodies lack scales. The adipose fin is well developed.
Many species of Pimelodidae have juvenile forms that appear differently from their adult forms in color pattern, as well as body shape. Brachyplatystoma species have specialized pelagic young with greatly elongated barbels and fin filaments, and strongly ornamented pectoral spines. Other large pimelodids, such as Pseudoplatystoma, Sorubim, and Sorubimichthys, whose young inhabit vegetated, marginal waters, have distinctive cryptic coloration patterns and much enlarged caudal and pectoral fins.
Relationship to humans
Because of their large size in many species, pimelodids are an important food fish in South America. Many species have been hybridized through the use of hormones in an effort to get even larger fish. This same size factor also makes them very popular for sport fishing.
Despite the looming danger of size in many species, pimelodids remain a popular home aquarium fish. Controversy exists over whether or not many of the larger species should be sold in the hobby because of their adult size. Also, some disagreement occurs over hybrids appearing in the hobby, as well. Many species are hardy and easy to take care of. However, care should of course be taken on what other fish to house pimelodids with, as they do not hesitate to eat other fish that are small enough.
- Garavello, Julio Cesar (2005). "Revision of genus Steindachneridion (Siluriformes: Pimelodidae)" (PDF). Neotropical Ichthyology 3 (4): 607–623. doi:10.1590/S1679-62252005000400018.
- Buitrago-Suárez, Uriel Angel; Burr, Brooks M. (2007). "Taxonomy of the catfish genus Pseudoplatystoma Bleeker (Siluriformes: Pimelodidae) with recognition of eight species" (PDF). Zootaxa 1512: 1–38. Retrieved 2009-06-24.
- Nelson, Joseph, S. (2006). Fishes of the World. John Wiley & Sons, Inc. ISBN 0-471-25031-7.
- Froese, Rainer, and Daniel Pauly, eds. (2007). "Pimelodidae" in FishBase. Mar 2007 version.
- Sullivan, JP; Lundberg JG; Hardman M (2006). "A phylogenetic analysis of the major groups of catfishes (Teleostei: Siluriformes) using rag1 and rag2 nuclear gene sequences". Mol Phylogenet Evol. 41 (3): 636–62. doi:10.1016/j.ympev.2006.05.044. PMID 16876440.
- Lundberg, John G.; Akama, Alberto (2005). Buth, D., ed. "Brachyplatystoma capapretum: a New Species of Goliath Catfish from the Amazon Basin, with a Reclassification of Allied Catfishes (Siluriformes: Pimelodidae)" (PDF). Copeia 2005 (3): 492–516. doi:10.1643/CI-04-036R1.
- Lundberg, John G.; Parisi, Béatrice M. (2002). "Propimelodus, new genus, and redescription of Pimelodus eigenmanni Van der Stigchel 1946, a long-recognized yet poorly-known South American catfish (Pimelodidae: Siluriformes)" (PDF). Proceedings of the Academy of Natural Sciences of Philadelphia 152: 75–88. doi:10.1635/0097-3157(2002)152[0075:PNGARO]2.0.CO;2.
- Stewart, Donald J. (1986). "Revision of Pimelodina and Description of a New Genus and Species from the Peruvian Amazon (Pisces: Pimelodidae)". Copeia 1986 (3): 653–672. doi:10.2307/1444947. JSTOR 1444947.
- Ribeiro, Frank R.V.; Lucena, Carlos A. S.; Lucinda, Paulo H. F. (2008). "Three new Pimelodus species (Siluriformes: Pimelodidae) from the rio Tocantins drainage, Brazil". Neotropical Ichthyology 6 (3): 455–464. doi:10.1590/S1679-62252008000300019.
- Lundberg, John G.; Nass, Pedro; Mago-Leccia, Francisco (1989). "Pteroglanis manni Eigenmann and Pearson, a Juvenile of Sorubimichthys planiceps (Agassiz), with a Review of the Nominal Species of Sorubimichthys (Pisces: Pimelodidae)". Copeia 1989 (2): 332–344. doi:10.2307/1445429. JSTOR 1445429.
- Lundberg, John G.; Berra, Tim M.; Friel, John P. (March 2004). "First description of small juveniles of the primitive catfish Diplomystes (Siluriformes: Diplomystidae)" (PDF). Ichthyol. Explor. Freshwaters 15 (1): 71–82. Retrieved 14 July 2014.