Two evolutionary grades are found in this family; micropredators (predators of very small organisms like aquatic insect larvae) and herbivores have a nonprotractile upper jaw and a deep to shallow body, while carnivores have a movable upper jaw and an elongated body.[1] Although the herbivores primarily feed on plant material, these species often have omnivorous tendencies. The carnivores include specialized fish-eaters (genus Mesoborus), fin-eaters (Belonophago, Eugnathichthys and Phago) and species that will feed on both whole fish and fins (Ichthyborus). The fin-eaters attack other fish, even ones that are much larger, where they bite off pieces of fins with their sharp teeth.[2][3][4]
The fish in Distichodontidae vary greatly in size among species, with the smallest micropredators being less than 8 cm (3.1 in) in length, and the largest herbivores can reach up to 83 cm (33 in).[5]
^Lavoué, S.; M.E.Arnegard; D.L. Rabosky; P.B. McIntyre; D. Arcila; R.P. Vari; M. Nishida (2017). Trophic evolution in African citharinoid fishes (Teleostei: Characiformes) and the origin of intraordinal pterygophagy. Molecular Phylogenetics and Evolution 113: 23-32. doi:10.1016/j.ympev.2017.05.001
^Matthes, H. (1961). Feeding Habit of Some Central African Freshwater Fishes. Nature 192: 78–80.
^Arroyave, J.; M.L.J. Stiassny (2014). DNA barcoding reveals novel insights into pterygophagy and prey selection in distichodontid fishes (Characiformes: Distichodontidae). Ecology and evolution 4(23): 4534–4542. doi:10.1002/ece3.1321
^Weitzman, S.H.; Vari, R.P. (1998). Paxton, J.R.; Eschmeyer, W.N. (eds.). Encyclopedia of Fishes. San Diego: Academic Press. p. 101. ISBN0-12-547665-5.
^Musschoot, T. & Snoeks, J. (2016): Re-establishment of the genus Monostichodus Vaillant 1886 (Characiformes, Distichodontidae). Journal of Fish Biology, 90 (3): 1080-1082.
