A jewel-like dartfish with a pale lavender-pink body, yellow face, and violet-edged fins — the rarest and most prized of the firefish. Peaceful and reef-safe, but timid, a determined jumper, and pricier and slightly more delicate than its commoner relatives.
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Small, peaceful, reef-safe marine fish (firefish and relatives) that hover above the substrate and dart into rockwork crevices when alarmed. Hardy and beginner-friendly, they are notorious jumpers and require a tightly covered aquarium.
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.
Photo coming soon
Minimum
Pair nano reef
30 gal / 114 L nano reef
Nemateleotris helfrichi reaches 2.5 in and is a rare, expensive firefish. 30-gal nano reef minimum with mature live rock, rubble hides, tight lid (jumpers), and peaceful tankmates only.
Photo coming soon
Recommended
Reef pair display
55 gal / 208 L reef
55-gal reef with a bonded pair, rubble hides, deep sand bed, peaceful tankmates, and gentle flow. Striking purple/yellow display fish — best in deep mature reefs.
Photo coming soon
Ideal
Deep-reef display
75 gal+ / 284 L+ deeper reef
75-gal+ deeper reef (>20 in tall) with deep aquascape, peaceful community, and a bonded pair. Closest to the deep-reef habitat they come from.
Life & growth stages
How this animal changes through its life — each stage often has its own care, diet and space needs.
Photo coming soon
Egg
Fish eggs are small, translucent spheres, often laid in clutches on plants, substrate, or in a nest — or carried/brooded by a parent in livebearing and mouth-brooding species. A dark eye spot and the curled embryo become visible inside as development progresses.
Photo coming soon
Fry
Newly hatched fry are tiny and semi-transparent, frequently still carrying a yolk sac that fuels them before they feed freely. They lack full fin structure and adult coloration, staying near cover until they can swim and forage on their own.
Photo coming soon
Juvenile
Juveniles look like miniature adults but with developing fins and muted or different markings; many species shift pattern and color as they mature. Growth is rapid at this stage given clean water and steady feeding.
Adult
Adults show the species' full size, finnage, and mature coloration, and are sexually mature. Many fish develop sex-specific differences in size, color, or fin shape, which can intensify during breeding.
Habitat & enclosure
A single Helfrich firefish can be kept in a 20-gallon (75 L) or larger reef system; 30 gallons gives more security. As with all firefish, a fully enclosed lid or fine mesh top is non-negotiable because they are accomplished jumpers and will leap from any open gap when startled. Provide live rock with small caves and crevices so the fish has a bolt-hole to dart into.
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 flow. This deeper-water species especially appreciates a calm, established tank with subdued aggression and plenty of cover.
Substrate
A bed of fine aragonite sand suits this near-bottom hoverer. Aquascape with live rock providing small caves and crevices so the fish always has a bolt-hole within reach.
Equipment & setup
Standard reef filtration with a protein skimmer, a reliable heater, and moderate flow suit this small fish well. Reef lighting is fine; the critical addition is a fully sealed lid or fine mesh top, as firefish are dedicated jumpers.
Diet
Helfrich firefish are micro-carnivores and zooplankton feeders. Offer a varied diet of frozen mysis shrimp, brine shrimp, copepods, finely chopped meaty seafood, and quality marine flakes or small pellets, fed in small portions one to two times daily. Enriched frozen foods help maintain condition and color.
They are timid feeders easily outcompeted by boisterous tankmates, so ensure they get their share, ideally in a peaceful community. Frequent small feedings suit their small size and nervous nature.
Behavior & temperament
Helfrich firefish are peaceful, shy, and well suited to calm reef tanks, hovering just above the rockwork and flicking the tall first dorsal spine, then darting to cover when alarmed. They are completely reef-safe and ignore corals and ornamental invertebrates. They can be kept singly or as a bonded male-female pair, but two unpaired individuals usually fight, so keep a single fish or a true pair.
They thrive only with gentle tankmates and ample hiding spots; in tanks with aggressive or fast fish they hide constantly and may refuse food. Multiple sightlines and bolt-holes are the key to keeping them confident and visible.
Health
Helfrich firefish are slightly more delicate than the common firefish and need careful acclimation to settle and feed. The leading cause of loss is jumping from an uncovered tank, so a secure lid is essential. They are also susceptible to marine ich (Cryptocaryon) and velvet, especially when stressed by bullying or poor acclimatization.
Chronic stress from aggressive tankmates or lack of cover leads to hiding, refusal to eat, and slow decline. Quarantine new fish, drip-acclimate slowly to stable parameters, provide abundant cover, and choose peaceful tankmates to keep them healthy.
Tips, DIY & hacks
A tight, gap-free lid is the single most important piece of equipment for this jumper. Drip-acclimate slowly, quarantine before adding to the display, and introduce it to a peaceful, established tank where timid feeders won't be outcompeted; keep one fish or a confirmed pair.
