Dartfish – Ptereleotrinae – are a small, colorful sub-family of fish that typically live in saltwater and are fairly peaceful when interacting with most other species. These goby-like fish were briefly re-categorized as a family, but have recently been reincorporated into the family Microdesmidae as a sub-family. They only reach a length of about 4 inches, and their colorful, unique, slightly elongated bodies and smooth texture have attracted divers and researchers to study them closely. Their colors can range from shades of yellow, green and red, to blue, orange, purple and black, or combinations of 2, 3 or more of the brighter shades of these colors, depending on the species. The fish thrive in habitats and areas with large swimming spaces and plenty of hiding places they can use to avoid predators.
Typically, dartfish are carnivores. Most species do very well when feeding on krill and various types of shrimp – primarily brine shrimp and mysis shrimp. They can adapt, however, and readily feed on most small invertebrates depending on what their habitat has to offer. Because of their small size and relatively benign nature, dartfish never feed on other fish, and usually prefer fleeing when attacked.
Dartfish are a parental species of fish – they care for their young and guide their development through their earlier stages of life. They lay eggs in small caves and crevices protected from predators, and they are known to closely protect their eggs both before and after the young ones hatch. Although it is easy to identify the location where dartfish are most commonly known to lay eggs and spawn, little is known about the actual reproduction process and the way parents tend to their young.
The place of origin for all types of dartfish is believed to be the Indo-Pacific, an area abundant in reef fishes that require stable environments and temperatures in order to thrive. Most species of dartfish can, however, be found in regions abundant in coral reef throughout the world, which can easily provide them with the space, habitat, hiding places and nourishment that the gobies require. Aside from the Indo-Pacific, dartfish (Ptereleotrinae) can also be located in the waters of Panama, as well as many other primarily tropical locations in the Eastern Central Pacific.