Kurtus

Kurtus is a genus of percomorph fishes, called the nurseryfishes, forehead brooders, or incubator fish, native to fresh, brackish and coastal marine waters ranging from India, through southeast Asia to New Guinea and northern Australia. Kurtus is currently the only known genus in the family Kurtidae,[1][2] one of two families in the order Kurtiformes.[3] They are famous for carrying their egg clusters on hooks protruding from the forehead (supraoccipital) of the males, although this only has been documented in K. gulliveri and available evidence strongly suggests this is not done by K. indicus (where the hook likely also is too small to carry embryos).[4] Females do not have a hook.[4]

Male Nurseryfish with embryos - photographed inside net by Time M. Berra

Kurtus
male Indian humphead (K. indicus)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Kurtiformes
Family:	Kurtidae Bleeker, 1859
Genus:	Kurtus Bloch, 1786
Type species
Kurtus indicus Bloch, 1786
Synonyms
Cyrtus Minding, 1832 Curtus (misspelling)

In addition to the egg hook, the kurtid gas bladder is enclosed in a tubular bony structure evolved from the ribs. In both species, the back is elevated into a hump shape.

Despite their unusual reproductive habits, little is known about these species. Historically they have proven very difficult to keep alive in aquaria, although recent success with K. gulliveri has been achieved by Tokyo Sea Life Park in Japan.