Pterosynchiropus splendidus, the fish commonly known as Mandarin goby, is actually not a goby at all. The goby species all belong to the family Gobiidae, while the Mandarin goby is a member of the family Callionymidae, the dragonet family. The Mandarin goby is therefore also referred to as the Mandarin dragonet. It is also known as Green Mandarinfish, Stripped Mandarinfish and Psychedelic fish – all three names based on its remarkable appearance.
The name Callionymidae is derived from the Greek words “kallis” which means beautiful, and “onyma”, which means name. The name is aptly chosen, since this group comprises some of the most beautiful and astonishingly looking fishes in the ocean. The dragonets – the little dragons – have triangular heads with big eyes and a big mouth. The tail fin is tapered and shaped like a fan, and the rest of the fins are also large, elongated and very fancy. The first high dorsal fin is very often equipped with four spines, and in male dragonets the first spine is often decorated with filamentous extentions. In addition to this showy body shape, the dragonets typically display a vivid coloration with dramatic and cryptic patterns.
The Mandarin goby is certainly no exception from this general description of the dragonets. It is considered one of the most striking fish species found in reef aquariums and is one of the most commonly sold species in the saltwater aquarium trade. The body of the Mandarin goby is green or blue, or combinations of both colors, and is spectacularly decorated with orange wavy lines that run across it. The tail has a bright red coloring and an intense blue edge. Among the main body colors, you can often find other shades as well.
The Mandarin goby usually grow up to 3 inches long, and males grow larger than females. The males can also be distinguished on their big and pointed dorsal fin. This fin is however only occasionally displayed. Most sources agree that you need at least a 55 gallon aquarium with 50 lbs of live rock to house your Mandarin goby. Keep the water temperature between 76 and 82° F.
In the wild, these fishes are found in pair or groups. Keeping a group of Mandarin gobies does however require a large aquarium, and Mandarin gobies are therefore more commonly kept in pairs or singly. Keeping two males together can result in a lot of fighting and should be avoided. Regardless of sex, the Mandarin goby is not aggressive towards other reef inhabitants and is seldom harassed by other fish.
Wild Mandarin goby is found in the Pacific Ocean between the Philippines and Australia, and lives on sandy bottoms near reefs. They will spend their time by meticulously examining the sand and live rock in search for food. This means that they can be hard to feed in aquariums, since the food will usually be devoured by faster species before the Mandarin gobies have a chance to find it.
Starvation is the main reason behind premature Mandarin goby death in reef aquariums, but you can prevent this by understanding the true nature of the Mandarin goby. Wild Mandarin gobies will eat nothing by live copepods and amphipods. If you place a Mandarin goby in a newly setup reef aquarium, there will most likely be too few copepods and amphipods around to sustain it. A well established reef aquarium is therefore a more suitable home. Also keep in mind that a nutrient rich reef aquarium usually has a larger population of copepods and amphipods compared to a lean aquarium.
You can increase the copepods and amphipod population by creating a so called “Pod Pile”. A Pod Pile is a small pile formed by rocks. Every couple of days, you place a small amount of chopped shrimp or similar food inside the pile. Copepods and amphipods will shelter inside the pile and multiply more rapidly since they have constant access to plenty of food.
Some aquarists have managed to train their Mandarin gobies to accept blood worms and frozen brine shrimp, but since the Mandarin goby is a slow scavenger you have to make sure that it actually gets the food. In many cases, the treats will be gulped down by faster fish.
If you purchase a healthy Mandarin goby and manage to make it eat sufficient amounts of food in the aquarium, you will have a hardy reef inhabitant that is surprisingly resilient towards many common aquarium problems, e.g. marine Ich. Finding a healthy Mandarin goby can however be hard, since many pet stores do not know how to provide their Mandarin goby with enough food. When you purchase a Mandarin goby that has lived in a pet store, it will therefore most likely be half starved. If the Mandarin goby has been trained onto frozen food in the pet store, it is probably well nourished. If the belly is sunken, it is probably famished.
Mandarin gobies have spawned in captivity. During the spawning period, the male will look his best to impress the female. Mandarin goby fry are tiny and need an extremely small first food. Even rotifers can be too big for the fry to consume.