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Nemateleotris decora

Elegant firefish

The elegant firefish, known in Italian as ghiozzo di fuoco elegante 9, is a small goby (family Gobiidae) 1 reaching at most 9 cm. 2 The front of the body is pale and the rear dark, the snout is violet and the fins carry red stripes edged with purple. 4 It often lives in pairs on open bottoms at the foot of deep reef slopes, where it eats zooplankton and dives into a burrow at the first sign of danger. 2 4

GobiidaeIUCN: Least concern
Nemateleotris decora

At a glance

Data from the scientific sources listed at the bottom.

Depth in the wild

25–70 m

0 m20 m40 m60 m80 m100 m

Size

up to 9 cm

0246810

maximum total length

Temperature in the wild

23–27 °C

18 °C34 °C

Where it lives

Red SeaWestern Indian OceanEastern Indian OceanCentral Indo-PacificWestern PacificCentral PacificEastern PacificWestern AtlanticEastern AtlanticMediterranean

Indo-Pacific: from Mauritius to Samoa, north to the Ryukyu Islands and south to New Caledonia. 2 Fishes of Australia adds the Red Sea and, for Australia, the northern Great Barrier Reef, the Coral Sea and the Cocos (Keeling) and Christmas Islands. 4 It has also been recorded at Pohnpei, in Micronesia. 7 FishBase notes that the Indian Ocean and Red Sea population used to be considered a separate species, N. exquisita, 2 a name that WoRMS, however, still lists as valid. 11

Conservation

NEDDLCNTVUENCREWEX

IUCN Red List: least concern (2015). Red List data taken from FishBase and GBIF. 2 8 It does not appear in the CITES lists checked on Species+. 10

How to recognise it

Tap a number on the photo: the key explains what to look for.

12345
  1. 1Violet snout the violet continues as a stripe over the head; here the lights make it paler 4
  2. 2Pale front pale grey, here more lilac because of the blue lights 4
  3. 3Darker rear in the sources it is blackish purple; in the photo the contrast is weaker 4
  4. 4Dorsal fin stripe broad and red, edged with purple 4
  5. 5Anal fin stripe same pattern as the dorsal fin 4

Life in the wild

Where it is found

Deep slopes along the coast and on the outer side of the reef, with moderate to strong currents: it stays on hard, open bottoms at the foot of the wall and on patches of sand and rubble. 2 4 It usually lives between 25 and 70 m, with a stated limit of 100 m. 2

What it eats

It eats zooplankton, mainly copepods and crustacean larvae. 2 The Pohnpei survey also classes it among plankton-feeding fish. 7

Behaviour

It is seen alone or, more often, in pairs. 2 4 If frightened it darts into a hole or burrow. 2 4

Reproduction

Separate sexes and external fertilisation. 3 It forms stable pairs; it spawns in a nest and parental care falls to the male. 2 3

In the aquarium

From the experience of the BallingMania community.

Community rating
Swimming level
lowmediumhigh
Coral compatibility
lowmediumhigh
Aggression
lowmediumhigh
Care difficulty
lowmediumhigh
Original sheet

A small, very colourful, hardy and peaceful fish belonging to the family Microdesmidae, coming from the Philippines and the north-eastern coast of Australia.

Acclimatisation and settling into the tank are fairly demanding, but once this phase is over it becomes hardy and fairly long-lived.

It adapts very well to living with fish of other kinds of the same size and peaceful temperament, but it becomes extremely aggressive with its own kind.

It is fairly resistant to parasites, but if the tank shows excessive nitrate and phosphate levels it loses colour and liveliness.

We can classify this fish as Reef Safe without any doubt, because it shows no interest in eating the invertebrates kept in the tank.

During the settling-in period it prefers frozen food (brine shrimp and mysis), but once acclimatised it does not refuse granular and/or flake food.

photo by: Ciro Murino

What studies say about keeping it

Data from an aquaculture study, not advice for a home aquarium. Madhu and Madhu report the first scientific captive breeding: fish of 6-10 cm in 500 L tanks at about 29 °C formed 4 pairs in 6 months; the pairs, moved to 250 L tanks, spawned after another 6 months. 5 Each spawning contained 400-500 eggs, guarded mainly by the male; hatching came after 96 hours at about 28 °C, with 93-98% success. 5 Newly hatched larvae measured about 1.9 mm: the best survival (66%) was achieved with Euplotes ciliates and then rotifers, followed by Artemia nauplii, and metamorphosis took place 35 to 40 days after hatching. 5 The adults were given cooked squid, shrimp and mussel, raw fish roe and live adult Artemia. 5

Did you know?

The name decora comes from Latin and means elegant, beautiful: it refers to its colours. 2 4
The species was described in 1973 from material from Augulupelu Reef, in Palau, at a depth of 52 m. 4
Its mitochondrial genome has been sequenced: it is 16,502 base pairs long and the authors suggest it as a useful marker for studies on relationships between species. 6

Sources

  1. Froese R., Pauly D. (eds.), via WoRMS (2026). Nemateleotris decora Randall & Allen, 1973. World Register of Marine Species.
  2. Froese R., Pauly D. (eds.) (2026). Nemateleotris decora, Elegant firefish. FishBase.
  3. Froese R., Pauly D. (eds.) (2026). Reproduction of Nemateleotris decora. FishBase.
  4. Bray D.J. (2025). Nemateleotris decora in Fishes of Australia. Museums Victoria.
  5. Madhu K., Madhu R. (2014). Captive spawning and embryonic development of marine ornamental purple firefish Nemateleotris decora (Randall & Allen, 1973). Aquaculture.
  6. Wang F.Y., Wang T.Y., Liao T.Y., Liu M.Y. (2016). The complete mitochondrial genome sequence of Nemateleotris decora (gobiiformes, gobiidae). Mitochondrial DNA Part A.
  7. Coleman R.R., Copus J.M., Coffey D.M., Whitton R.K., Bowen B.W. (2018). Shifting reef fish assemblages along a depth gradient in Pohnpei, Micronesia. PeerJ.
  8. GBIF Secretariat (2026). Nemateleotris decora, IUCN Red List category. GBIF.
  9. GBIF Secretariat, da Catalogue of Life (2026). Nemateleotris decora, nomi comuni. GBIF.
  10. UNEP-WCMC, Segretariato CITES (2026). Search for Nemateleotris decora in the CITES lists. Species+.
  11. Froese R., Pauly D. (eds.), via WoRMS (2026). Nemateleotris exquisita Randall & Connell, 2013. World Register of Marine Species.

Sources checked on 5 November 2026. Community texts and ratings are kept separate from the scientific data.

Download the original sheet (Italian)All species