Species NamePtereleotris (Genus that includes various species)
Common NameDartfish
Care LevelModerate
Lifespan5-7 years
Adult Size2-4 inches
DietCarnivore (small invertebrates, zooplankton)
Minimum Tank Size30 gallons
Temperature72°F – 78°F (22°C – 25.5°C)
Water ConditionspH 8.1-8.4, Salinity 1.020-1.025, dKH 8-12

About the Dartfish – Species Summary

Dartfish, members of the Ptereleotris genus, are sleek, slender, and vibrantly colored marine fish that find their home in the tropical waters of the Indo-Pacific region. Graceful swimmers, dartfish frequently dart in and out of crevices and burrows, an activity that led to their evocative name. They typically inhabit sandy or rubble-strewn bottoms near coral reefs. Their vivid colors, combined with their lively behavior, make them captivating additions to a reef tank, though their somewhat skittish nature requires an environment that caters to their need for safety and hiding spots.

Dartfish Lifespan

When provided with the right care, dartfish generally live for about 5 to 7 years in captivity. Their lifespan can be extended by maintaining optimal water conditions, a balanced diet, and a stress-free environment.


The dartfish boasts an elongated body with vibrant colors that vary by species. The most common colors range from deep blues, bright yellows, to fiery reds. Many also exhibit beautiful gradations of color along their bodies. Their elongated dorsal and anal fins, coupled with their slender build, give them an almost arrow-like appearance, further emphasizing their “darting” behavior.

Average Size

Most dartfish species will grow to an adult size of between 2 and 4 inches, though size can slightly vary depending on the specific species and the conditions of their environment.

Dartfish Care

Tank Size

A minimum tank size of 30 gallons is recommended for dartfish, though if you wish to keep a group or have other tank mates, a larger tank is advisable.

How To Set Up Their Tank

Dartfish thrive in a tank that mimics their natural habitat. This means providing plenty of hiding spots with live rocks, caves, and crevices. A sandy substrate is crucial as these fish often burrow or dive into the sand when threatened. Gentle to moderate water flow replicates their natural environment and allows them to display their natural swimming behavior.

Lighting Requirements

Moderate lighting is suitable for dartfish, though they’re not as dependent on lighting as some coral or plant species. However, if the tank contains corals, the lighting should cater to the coral’s needs.


For dartfish, maintaining a pH level between 8.1 to 8.4 is essential for their health and well-being.


Maintain a stable temperature between 72°F and 78°F (22°C to 25.5°C) for dartfish. Regular monitoring and the use of aquarium heaters can help in ensuring consistency.

Water Parameters

The water’s salinity should be kept between 1.020 and 1.025. The carbonate hardness (dKH) is ideally maintained between 8 and 12.

Disease Potential

Like most marine fish, dartfish are susceptible to common fish diseases like marine ich and velvet. Implementing a quarantine process for all new tank inhabitants, regular observation, and maintaining excellent water quality can reduce the risk of disease outbreaks.

Food & Diet

Being carnivores, dartfish primarily feed on small invertebrates and zooplankton in the wild. In captivity, a varied diet of high-quality flake foods, micro pellets, and live or frozen foods like brine shrimp or mysis shrimp ensures they receive the necessary nutrients.

Behavior and Temperament

Dartfish are peaceful yet active fish. They’re known for their darting behavior, quickly zipping in and out of hiding spots. This behavior, combined with their tendency to stay near the bottom of the tank, makes them entertaining to watch. They can, however, be timid and skittish, especially in a new or overly active environment.

Tank Mates

Because of their peaceful nature, dartfish should be paired with similarly tempered tank mates. Avoid aggressive or overly large fish that might see them as prey or stress them out. Many reef inhabitants, including various invertebrates and corals, coexist harmoniously with dartfish.


Breeding dartfish in captivity can be challenging due to their specific environmental needs and the delicate nature of the fry. They are egg layers and tend to choose secluded spots or burrows for laying. If you’re aiming for breeding, providing them with a quiet environment, optimal water conditions, and a varied diet can increase the chances of success. The male typically guards and tends to the eggs until they hatch.

Dartfish FAQs (Frequently Asked Questions)