Leaffishes are an anomalous small group of fishes, at times linked, placed with the similar-appearing Labyrinth Fishes (Anabantoids), though having little taxonomic affinity with that group. Both have large heads, with matching mouths that are protractile (more so in the Leafs)... Both resemble leaves in water at rest.
Nandids comprise ten species in seven genera... principally freshwater (some tending to brackish), northeastern South America, western Africa, southern Asia. Badids make up two genera with fifteen species in the Ganges, Brahmaputra and Mahanadi basins, in Nepal, India, and Bangladesh; and, Irrawaddy in Myanmar and China. Polycentrids are two monotypic genera of South American fishes.
Most a few inches in length, one to some eight inches (Pristolepis fasciata).
Hardy fishes if received in good condition (rare) and provided with dedicated quarters (voracious predators that like a peaceful setting...). Commonly lost from handling, shipping trauma, secondary infection.
Anon. 1973. Care and Breeding. The other Leaf Fish (Polycentrus). A.D.I. 2(2):73.
Armbrust, Walter. 1977.Like a brown leaf, the Leaf Fish, perfect camouflage (Monocirrhus polyacanthus). Aquarium Digest Int'l. #17, 3, 1977.
Howe, Jeffrey C. 1998. Original Descriptions (column). Nandus oxycephalus Ng, et al. 1996. FAMA 10/98.
Quinn, John R. 1988. Lord love a Leaffish. TFH 1/88.
Taylor, Edward C. 1980. Leaffish... More or less. The Family Nandidae and subfamily Polycentrinae. FAMA 2,3,5/80.