A dragonet is a small perciform marine fish from the callionymidae family that is found in the waters surrounding the eastern coast of Africa and the island of Sumatra. There are many different species of dragonet, but most are small and range between 2 to 3 inches (5 to 8 centimeters) in size. Three of the species in particular — the starry dragonet, spotted mandarin fish and green mandarin fish — are popular choices for reef aquarium enthusiasts.
Most dragonets have extremely bright and flamboyant coloration. The green mandarin fish typically has green, blue, and orange patterns with dark blue fins. The spotted mandarin fish is also green, with blue, black and orange spots covering its body. The starry dragonet is less striking than others and is usually white with patches of red and brown. In the wild, these fish are usually found along reefs close to the shore and in lagoon areas. It is a bottom dweller and is usually seen in pairs or in groups among dead coral and rocks where it can hide from predators. It is a carnivorous fish and will eat small crustaceans.
Despite its popularity, the dragonet is an extremely difficult fish to keep alive and healthy in a marine aquarium and is not recommended by most fish experts for beginner or even advanced aquarium keepers. While most fish kept in aquariums can adapt to flake food or brine shrimp, most dragonets kept in aquariums will only eat live prey. Even if it develops a taste for pre-killed food or flakes, it typically won't get a chance to eat it in a community tank because it is a slow eating fish.
An aquarium with a population of dragonetes will need a steady supply of copepods and amphipod crustaceans or the fish will most likely starve. While it is compatible with most other species of non-aggressive fish, it can be difficult to keep multiple dragonets in one aquarium together. This is especially true with males, which can become territorial.
The water conditions needed to keep a dragonet alive are also strict, further indicating that it is not a fish for beginners. Dragonets require an aquarium that is at least 30 gallons in size, with plenty of hiding spaces and a natural sand substrate. Without hiding spaces the fish will become stressed and most likely die. It can only survive in a very small temperature range, between 75 and 79 degrees Fahrenheit (23 to 26 Celsius), and in with a steady pH level between 8.1 and 8.4.