Family : Microdesmidae
Text © Giuseppe Mazza
English translation by Mario Beltramini
The spectacular Fire goby or Fire darfish (Nemateleotris magnifica Fowler, 1938) belongs to the class of Actinopterygii, the ray-finned fishes, to the order of Perciformes and to the small family of Microdesmidae, which counts a dozen of genera and almost 90 tropical species with the elongated and thin body, at times almost anguilliform, mainly marine, but also, sporadically, of fresh or brackish water.
The name of the genus “nemateleotris” comes from the Greek “nematos” = thread and “eleotris”, a genus assigned to fishes having an elongated structure (family Eleotridae) which, in turn, comes from the name of a fish of the Nile River. Concluding, it’s an elongated fish with a filiform filament.
For the etymology of the species “magnifica”, the Latin female of “magnificus” = pompous, grandiose, sublime, beautiful, there are no doubts: just look at the photo.
It has a very vast distribution in the tropical waters of the Indo-Pacific. We find it, for instance, along the eastern African coast, from South Africa to East Africa, to the Comoro, Seychelles, Réunion, Mauritius, Chagos, Maldives, Cocos, Christmas and Andaman islands. Then, in India, Sri Lanka, Indonesia, Australia, New Guinea, Micronesia, Marshall Islands, Philippines and Guam Island, up to the southern part of Japan. Eastward, it has colonized the islands of Samoa, Tonga and Cook, French Polynesia and the Pitcairn Islands, which are also the southern limit in the Pacific after Vanuatu, Fiji and New Caledonia.
It loves the detrital or rocky bottoms provided they have suitable caches. When it leaves its den, often dug into the sand, it goes, at the right moment, in the midst of the currents, on the outer slope of the reefs, where the zooplankton it eats passes by. Usually around the 5-30 m of depth, but, exceptionally, it can go down up to 60 m.Morpho-physiology
The fusiform, elongated body, with big eyes and roundish profile of the head, does not exceed the 9 cm.
It shows two dorsal fins counting, totally, 7 spiny rays and 27-32 soft ones. The first, lance-shaped, slightly longer in the males, has the upper edge red and can raised vertically for intimidation. When folded, it almost touches the caudal peduncle. The second dorsal fin is low and elongated, symmetrical to the anal, which has only one spiny ray and 27-30 unarmed ones.
The ventral fins are also long and pointed, whilst the pectoral ones, transparent and fan-like, are absolutely normal. The caudal fin is rounded, dark red like the upper part of the dorsal, with two bluish traits that converge until they become parallel.
In the first half of the body the background colour is yellow-greenish, turning pearly towards the abdomen, and then quickly fades to red fire. After the eye, towards the back, we note a slight pale dotting with violaceous shades and an analogous dorsal stripe.
The adult fire globy lives in pair, but the juveniles often share the same den. It mainly nourishes of crustaceans and copepods larvae it catches with rapid flashes, hence the common name of fire darfish, taxonomically more exact, because apart a superficial resemblance, this fish has nothing to do with the globies which belong to the family of the Gobiidae.
The eggs are fecundated in a nest dug in the sand and the male keeps watch till the hatching. The populations can double in less than 15 months, and even if the fire globy is at times wildly fished with the poison for the domestic aquaria, the vulnerability index of the species is very low: just 10 on a scale of 100.