Common name: Monofin dartfish

General information

The Monospike Dartfish, scientifically known as Ptereleotris monoptera, is a small and peaceful marine fish that is well-suited for reef aquariums. It is characterized by its elongated body, striking blue to purple coloration, and a distinctive single spike on the first dorsal fin, which is where its common name derives from.

This species is not as common in the trade as some other dartfish, but it is appreciated for its peaceful demeanor and the flash of color it brings to the aquarium. It is a shy and reclusive fish that prefers the company of its own kind, often forming small groups in the wild.

Care

Monospike Dartfish require an aquarium with plenty of hiding places and a sandy substrate where they can retreat if frightened. They are jumpers, so a well-fitted aquarium lid is essential to prevent escape. These fish are best kept in small groups or pairs to help reduce stress. They are not aggressive and can be housed with other peaceful tank mates.

A varied diet of small meaty foods such as mysis shrimp, brine shrimp, and finely chopped seafood is important for their health. They are generally hardy once acclimated but should be monitored for signs of stress or disease.

Reproduction

In the home aquarium, breeding Monospike Dartfish can be challenging. They are not commonly bred in captivity, and little is known about their reproductive habits. However, like many marine fish, they are likely to be pelagic spawners, releasing eggs and sperm into the water column where fertilization occurs.

Habitat

Ptereleotris monoptera is found in the Indo-Pacific region, from the Maldives to the Philippines, and as far south as Australia. They inhabit lagoons and seaward reefs, often seen hovering above the bottom in small groups or pairs. They prefer areas with moderate to strong currents and are typically found at depths ranging from shallow waters to about 40 meters.