Helfrichi Firefish - Nemateleotris helfrichi

Helfrichi Firefish (Nemateleotris helfrichi)

The Helfrichi Firefish, Nemateleotris helfrichi, is a stunning and highly sought-after marine dartfish, admired for its soft lavender body, bright yellow face, pinkish-purple tones and elegant upright dorsal fin. Also known as Helfrich’s Dartfish or Helfrich’s Firefish, this peaceful reef species brings beautiful colour and gentle movement to mature marine aquariums. It is more specialist and less commonly available than the standard Firefish, making it a premium choice for aquarists who can provide calm tank mates, stable water quality and a secure covered aquarium.

Common Name:
Helfrichi Firefish, Helfrich’s Firefish, Helfrich’s Dartfish, Helfrichi Dartfish, Helfrich Firefish.

Scientific Name (Latin):
Nemateleotris helfrichi

Maximum Size:
Around 6 cm, making it a small and delicate marine dartfish.

Water Type:
Marine

Origin / Natural Habitat:
Found in tropical Pacific reef regions, including parts of the west-central and south-eastern Pacific. In the wild, Helfrichi Firefish are usually associated with deeper reef slopes, rubble patches, sandy areas and hard open reef bottoms, often at depths below those occupied by more common firefish species. They are frequently seen hovering close to shelter, where they can quickly retreat if threatened.

Water Parameters:
Temperature: 24–27°C
pH Range: 8.1–8.4
Hardness or Salinity: SG 1.020–1.025

Temperament:
Peaceful and shy. Helfrichi Firefish are best kept with calm, non-aggressive marine fish and should not be housed with boisterous or predatory tank mates. They may be kept singly or as a confirmed pair, but multiple unpaired individuals can become territorial towards each other in smaller aquariums.

Diet:
Carnivorous planktivore. In the wild, this species feeds on small zooplankton and suspended food items in the water column. In the aquarium, offer a varied diet of frozen mysis shrimp, enriched brineshrimp, cyclops, copepod-based foods, finely chopped meaty marine foods and high-quality small marine pellets. Smaller, regular feeds are ideal, especially while the fish is settling.

Minimum Tank Size:
A practical minimum of around 75 litres is recommended for a single specimen, with larger aquariums preferred for pairs or mixed reef systems. The aquarium should include stable water quality, gentle to moderate flow, open swimming space and suitable caves or crevices for shelter.

Behaviour & Activity:
A graceful hovering dartfish that often positions itself just above the substrate or rockwork, facing into the water movement to intercept small foods. It may be shy when first introduced and can retreat quickly into a chosen cave or burrow if startled. Once settled with peaceful tank mates, it often becomes more visible and will spend time hovering in open water near its shelter. A tight-fitting lid is essential, as firefish are well known for jumping when frightened.

Reef Safe:
Reef Safe
Helfrichi Firefish are considered reef safe and do not normally nip corals, clam mantles or sessile invertebrates. They are an excellent choice for peaceful reef aquariums, provided they are not bullied by more assertive fish.

Special Requirements or Care Notes:
Best suited to mature, peaceful marine aquariums with secure lids and plenty of hiding places. Avoid aggressive tank mates, fast-feeding competitors and open-top aquariums. Newly introduced specimens can be shy, so ensure food reaches them and avoid excessive disturbance during the settling period. Due to their smaller size, delicate nature and premium availability, they are best kept in stable systems with careful stocking.

Suitable for:
Intermediate fishkeepers

Availability:
Premium marine species / Availability can vary due to collection, import and supplier availability

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Please note that Mother Nature is a wonderful thing, and variation in patterns and colours will occur — that is part of the unique beauty of these animals.