A new checkerboard cichlid from the Rio Tapajós

As far as it is known, Dicrossus sp. "Tapajos" is found only upstream of the São Luis de Tapájos rapids. Photos by Frank Warzel.

The members of the genus Dicrossus Agassiz, 1875, generally known in the literature as checkerboard cichlids, are among the most popular South American cichlids. These darting, rather graceful, fishes are nowadays being imported more frequently, in particular on account of their interesting patterning, but also because of their splendid finnage. In addition, they are very peaceful towards other aquarium occupants and thus appear well-suited to the community setup, but they are in fact basically rather delicate fishes, as becomes quickly apparent when an attempt is made to breed them (if not before). Thus, for example, Dicrossus filamentosus, which originates from a blackwater biotope, requires very acid water with minimal nitrate content. And aquarium decor which involves a bottom layer of scalded oak or beech leaves is not to everyone's taste. In their native waters, these fishes are commonly found in quiet riparian bays or residual pools with an accumulation of leaf litter, dead twigs, and the like. Their typical method of searching for food ­ as in the rather larger Crenicara species as well ­ consists simply of grubbing around in the leaves lying on the bottom. An individual leaf is seized by its edge and the fish then swims upwards just far enough for the leaf to begin slowly to tip over; in this way, it can turn over leaves that are much larger and heavier than itself. It would appear that these cichlids are searching for the small organisms that live beneath and among the layers of leaves, and which they pick up one at a time.