🐟 AquaticCare difficulty: BeginnerLegal complexity: Low
Firefish
Nemateleotris magnifica · also called Firefish Goby, Fire Dartfish, Magnificent Firefish, Red Firefish
A slender, elegant dartfish with a pale body, fiery red-orange tail, and a tall sail-like dorsal fin it flicks when alert. Peaceful and beginner-friendly, but a notorious jumper that requires a covered tank.
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Quick facts
| Size | Reaches about 3 in (7-8 cm) as an adult. |
| Lifespan | 3–5 years |
| Social needs | pair |
| Native region | Indo-Pacific |
| Origin | Old World |
| Climate | 🌴 Tropical |
| Water type | 🌊 Marine |
| Family | Microdesmidae |
| Genus | Nemateleotris |
Part of the Gobies
Small, mostly bottom-dwelling marine and brackish fish prized in aquaria for their hardiness, interesting behaviors, and roles such as sand-sifting, burrowing, or pairing with pistol shrimp. This grouping also includes goby-like specialty species sold under goby names.
Habitat & space requirements
From the minimum an animal needs to be kept humanely, up to the ideal setup. Bigger is almost always better — minimums are floors, not targets.
Life & growth stages
How this animal changes through its life — each stage often has its own care, diet and space needs.
Habitat & enclosure
A single firefish can be housed in a 20-gallon (or larger) reef system; 30 gallons gives more security and swimming space. The single most important requirement is a secure, fully enclosed lid or mesh top, because firefish are accomplished jumpers and a stressed fish will leap from any open gap. Provide live rock with small caves and crevices so the fish has a bolt-hole to dart into when threatened.
Maintain stable tropical reef conditions: temperature 72-78 F (22-26 C), pH 8.1-8.4, salinity 1.020-1.025 specific gravity, and moderate water flow over the rockwork. Firefish prefer to hover just above the substrate in the lower-to-mid water column near their shelter, so an aquascape with low overhangs and escape routes suits them best.
Substrate
A 1-2 inch bed of fine to medium aragonite sand suits this reef dartfish, which likes to dart into the substrate and rockwork for cover. Provide plenty of live rock with crevices it can dash into when startled.
Equipment & setup
Standard reef setup: a stable saltwater system (sg 1.024-1.026, 72-78 F) with a protein skimmer, good flow, and live rock biofiltration. A tight-fitting lid is essential because firefish are notorious jumpers; reef lighting and at least 20 gallons give them a secure home.
Diet
Firefish are micro-carnivores and zooplankton feeders. In captivity they accept a varied diet of frozen mysis shrimp, brine shrimp, finely chopped meaty seafood, copepods, and quality marine flakes or small pellets. Feed small portions one to two times daily.
They are not aggressive feeders and can be outcompeted by boisterous tankmates, so ensure they get their share. Enriched frozen foods help maintain body condition and the vivid tail coloration.
Behavior & temperament
Firefish are peaceful, timid, and well suited to calm community reef tanks. They spend much of their time hovering and rapidly flicking the tall first dorsal spine, retreating instantly to a rock crevice when startled. They are reef-safe and ignore corals and ornamental invertebrates.
They can be kept singly or as a bonded male-female pair, but two unpaired firefish often fight, so a single specimen or a true pair is best. With timid tankmates and plenty of cover they become confident; in tanks with aggressive fish they may hide constantly or refuse food. Multiple sightlines and bolt-holes are the key enrichment.
Health
Firefish are generally hardy once settled, but the leading cause of loss is jumping out of uncovered tanks, so a secure lid is essential. They are also susceptible to the usual marine parasites such as ich (Cryptocaryon) and velvet, particularly when stressed by aggressive tankmates or poor acclimatization.
Chronic stress from bullying or lack of hiding places leads to hiding, refusal to eat, and slow decline. Quarantine new fish, acclimate slowly to stable parameters, provide ample cover, and choose peaceful tankmates to keep firefish healthy.
Tips, DIY & hacks
Keep just one per tank unless you have a large system and add a bonded pair simultaneously, as they fight their own kind. They are shy and easily outcompeted, so house with peaceful tankmates and target-feed small meaty foods (mysis, enriched brine, finely chopped seafood); covering every gap, even filter cutouts, prevents carpet-surfing losses.