Mandarin Fish – Spectacular Marine Life

The ocean is full of an incredible variety of wonderful animals. Although many of the larger animals such as dolphins, whales, and manta rays get a lot of attention, some of the smaller denizens are equally as charismatic. In fact, it’s often the smallest of species that are the most spectacular. One of the most beautiful and eye catching animals underwater is less than a finger length in size. With its flambouyant colour scheme, the Mandarin Fish is one of the most beautiful fish in the sea. The Latin name of the mandarin fish, Synchiropus splendidus, even includes the word splendid to describe them.

What are Mandarin Fish?

The mandarin fish is a member of the dragonet family, a group of bottom dwelling fish that resemble gobies. They are found in shallow waters only in the western Pacific from Japan south to Australia. Mandarin fish reach a maximum size of around six centimeters and tend to live on or near branching coral or rubble. Their preferred habitat is branching corals which offer a variety of hiding places as well as a source of food. The main diet of these tiny fish consists of microscopic creatures such as worms and copepods. These organisms often live on the substrate or on corals which is where we find the mandarins.

These colourful fish tend to hide during the day as they are easy targets for predators. However, as dusk settles in they become active in the search of food. We often find them around 5pm moving along the spines of branching coral on the hunt. In fact, a dusk dive is always the best time to encounter these characters.

Mating Games

The reason for dusk being the best time to find them is simple: sex! Yes, that’s right, like many species of fish, mandarins tend to mate as the sun is setting. The brief period of time between day and night means there is respite from predators. Daytime predators are looking for a place to rest and night time predators haven’t yet gone on the hunt. This is the best time for mandarin fish to search for potential mates.

Males and females live in a small home range and often the males have a number of females living within their habitat. As the sun starts to sink below the horizon, the males put on a bit of a show by expanding their fins in order to attract a female. They may also run into competitor males which may result in fights involving a lot of biting and ripping of fins.

Eggs Floating Away

When the male mandarin fish finds an interested female the true fun starts. The male will actively swim in front or beside her and perform a “mating dance”. He may perform this dance with three or four females before he finds a willing partner. Once they decide to mate, they swim side by side on the coral or on the bottom for a moment before quickly rising into the water column. It’s possible to see how the fish begin vibrating as they rise before they reach their peak and suddenly dart toward the bottom.

The mating process happens in less than 10 seconds and many watchers don’t understand what they witnessed. However, if you look closely in the water column it’s possible to spot the gametes floating away. The fish have successfully mated! By doing this at night, the eggs have a better chance of floating away from potential predators to survive until hatching.

Finding Mandarin Fish in Indonesia

Once the mating is done, the fish quickly disappear into the shelter of the coral for the night. It’s important to look for this activity before dark or it will be missed. Therefore, on the Samata we offer this opportunity as a late afternoon dive rather than a night dive. During a true night dive we won’t be able to spot the elusive mandarin fish. There are several areas within Indonesia where we spot the, popular spots include Komodo, Banda Neira, and Raja Ampat. If you are cruising on the Samata with us during one of these itineraries then we will be more than happy to introduce you to these wonderful and spectacular fish!