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Banjo catfish are a family (Aspredinidae) of tiny South American catfish which live in the major tropical river systems of the continent. Most species of banjo catfish have round flat heads and long skinny tails—hence their distinctive name. Although various sorts of banjo catfish live in many different river habitats (from quick flowing channels, to murky stagnant backwaters, to brackish tidal basins) they generally utilize the same strategy of keeping still and allowing their camouflage to protect them. Although like all catfish, they lack scales, the Aspredinidae make up for this absence with rows of horny keratin tubercles which break up their profile and leave them well disguised. Additionally they can shed their skins! As omnivores they hunt tiny invertebrates as well as feeding on whatever they can scavenge. Members of the Amaralia genera of Banjo catfish are especially fond of the eggs of other species of catfish, which they actively seek out and vacuum up.
Perhaps because they are so partial to eating the eggs of other catfish, some banjo catfish have evolved special strategies to protect their own eggs. Female catfish in the subfamily Aspredininae wait until their eggs are fertilized and then attach the developing eggs to their belly. Three species of Aspredininae develop specialized fleshy stalks called cotylephores specifically for the purpose of exchanging nutrients and oxygen between the mother and the eggs.