The nurseryfishes or forehead brooders are a family (Kurtidae) of fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

 that are notable for carrying their egg clusters on hooks protruding from the forehead (supraoccipital) of the males. The family consists of just two species in the single genus Kurtus.

In addition to the egg hook, the kurtid gas bladder

Gas bladder

The swim bladder, gas bladder, fish maw or air bladder is an internal gas-filled organ that contributes to the ability of a fish to control its buoyancy, and thus to stay at the current water depth without having to waste energy in swimming...

 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; they do not survive long in aquaria

Aquarium

An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...

. Tim Berra

Tim Berra

Dr. Tim M. Berra is the author of the 1990 book, Evolution and the Myth of Creationism. Dr. Berra is Professor Emeritus of Evolution, Ecology and Organismal Biology at the Ohio State University...

 of Ohio State University

Ohio State University

The Ohio State University, commonly referred to as Ohio State, is a public research university located in Columbus, Ohio. It was originally founded in 1870 as a land-grant university and is currently the third largest university campus in the United States...

 has published several papers.

Species

The nurseryfish, Kurtus gulliveri Castelnau

François Louis de la Porte, comte de Castelnau

François Louis Nompar de Caumont LaPorte, comte de Castelnau was a French naturalist, known also as François Laporte or Francis de Castelnau.-Life:Born in London, he studied natural history in Paris...

, 1878, occurs in mangrove swamp

Mangrove

Mangroves are various kinds of trees up to medium height and shrubs that grow in saline coastal sediment habitats in the tropics and subtropics – mainly between latitudes N and S...

s, estuaries

Estuary

An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....

 and slow-moving turbid rivers of Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 and New Guinea

New Guinea

New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...

. It can grow to 63 cm.

The Indian hump head, Kurtus indicus Bloch

Marcus Elieser Bloch

Marcus Elieser Bloch was a German medical doctor and naturalist. He is generally considered one of the most important ichthyologists of the 18th century.- Life :...

, 1786 is found in marine waters from India

India

India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

's Coromandel Coast

Coromandel Coast

The Coromandel Coast is the name given to the southeastern coast of the Indian Subcontinent between Cape Comorin and False Divi Point...

 to Borneo

Borneo

Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....

. It is known to reach only 12.6 cm in length.