Nomorhamphus

Hemiramphidae
Freshwater halfbeak in aquarium
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Beloniformes
Family:	Hemiramphidae
Genus:	Nomorhamphus Weber & de Beaufort, 1922
Species:	Nomorhamphus australis Nomorhamphus bakeri Nomorhamphus brembachi Nomorhamphus celebensis Nomorhamphus hageni Nomorhamphus kolonodalensis Nomorhamphus liemi Nomorhamphus manifesta Nomorhamphus megarrhamphus Nomorhamphus pectoralis Nomorhamphus philippina Nomorhamphus pinnimaculata Nomorhamphus ravnaki Nomorhamphus rossi Nomorhamphus sanussii Nomorhamphus towoetii Nomorhamphus vivipara Nomorhamphus weberi

The freshwater halfbeaks of the genus Nomorhamphus are widely distributed in Southeast Asia, in particular the islands of the Philippines, Indonesia, and Sulawesi. They are all viviparous, producing small clutches of around a dozen fry about 10 to 15 mm long at birth. Females are generally larger than the males. In the largest species, such as Nomorhamphus liemi, the females are about 100 mm in length, whereas the males are about 60 to 70 mm in length. Males are also more brightly coloured than the females (often having red, black, or blue patches on their fins). Compared with many other halfbeaks, the lower mandible, or beak, is relatively short, on females in particular barely protruding beyond the length of the upper mandible. The males of some species (e.g., N. ebrardtii) have short, straight beaks, but those of others (e.g., N. liemi) have short beaks that curve downwards forming a shape often compared to a goatee beard by aquarists.

Nomorhamphus fish feed extensively on small insects, either in the form of aquatic larvae or as flying insects that have fallen onto the surface of the water. They are important predators on insects such as mosquitoes, so play a role in controlling malaria. Nomorhamphus fish are too small to be of value as food, but they do have some value as aquarium fish.

A young Nomorhamphus about seven days old and about 18 mm in length, lacks the prominent beak of the adults.

Reproduction

Nomorhamphus species are livebearing fish that practise internal fertilisation. The male is equipped with a gonopodium-like anal fin known as a gonopodium that delivers sperm into the female. The gestation period is about six weeks. The exact mode of reproduction ranges from ovoviviparity through to viviparity, and in some species, oophagy is known, as well (see section on reproduction in the halfbeak article). Only around ten to twenty embryos are developed at a time, but at birth these are fairly large (around 13 mm) and well developed, able to take small prey, such as Daphnia, immediately after birth.

Species

• Nomorhamphus australis
• Nomorhamphus bakeri
• Nomorhamphus brembachi
• Nomorhamphus celebensis
• Nomorhamphus hageni
• Nomorhamphus kolonodalensis
• Nomorhamphus liemi
• Nomorhamphus manifesta
• Nomorhamphus megarrhamphus
• Nomorhamphus pectoralis
• Nomorhamphus philippina
• Nomorhamphus pinnimaculata
• Nomorhamphus ravnaki
• Nomorhamphus rossi
• Nomorhamphus sanussii
• Nomorhamphus towoetii
• Nomorhamphus vivipara
• Nomorhamphus weberi

Further reading

• Scott, Peter (1997): Livebearing Fishes, Tetra Press, ISBN 1-56465-193-2

References

• FishBase entry for Nomorhamphus
• Report on keeping and breeding halfbeaks