Two-spotted gobies or Signigobius biocellatus are members of the Gobiidae family. This is a fairly large family consisting of over 2,000 individual species in over 200 genera. Two dots are indigenous to the Indo-Pacific. They range from the southern Philippines to Australia.

This species has the elongated cylindrical body that one would expect to find in a goby. One of the most interesting aspects of gobies is their wide variety of coloration and body patterns. Colons are yet another example of these variations. Compared to the exotic coloration typical of many gobies, this species has a rather bland appearance. It has a light tan body dotted with brown and pale orange markings of various shapes and sizes. This coloration causes it to blend in almost seamlessly with the backdrop of the ocean floor or while perched on top of a rock formation. The most distinctive feature of this species is its two dorsal fins. These fins stand upright on the fish’s back. They are taller than the actual body of the fish. Each of these fins has large false eyespots intended to confuse predators. When this fish is viewed from the side, it appears as if you are looking at the face of a fish two to three times its size. It is these two eyespots (ocelli) that the fish is named for. The aquarium industry also sells these fish under the names; twin-spotted goby, signal goby and crabeye goby.

Two points are bottom dwellers. As with many bottom dwellers, this is primarily a scavenger fish. These fish sift through the sand in search of food. They are also browsers. Two blobs use their mouths to carry away sand and debris in the construction of their burrows. An aquarium with an adequate supply of live rock and live sand as a substrate will emulate their natural habitat, provide them with a secondary food source, and prevent them from being accidentally harmed.

This is a small fish, exceptionally mild mannered. They only grow to an average length of 2.5 inches. They make wonderful additions to multi-species and marine reef aquariums. These gobies should not be housed with larger or even moderately aggressive fish. Unlike most bottom dwellers, colons are tolerant of other bottom-dwelling fish. However, they may exhibit territorial behavior towards conspecifics. A pair of roommates can be successfully housed together. Depending on your aquarium population, this species can be housed in as little as a 10-gallon tank. This is kind of short lived. Its half-life is only two years. Two points have a moderate level of care. They can be bred by intermediate saltwater aquarists.

Two spots are carnivorous. They should readily accept flake or pellet foods formulated for carnivores. To keep them healthy and vigorous, their diets should be supplemented with mysid or brine shrimp or any other supplements commonly given to marine carnivores. They need to be fed 1-2 times a day.

Two Spot Gobies Breeding

In the wild, this species is most commonly seen in pairs. They are monogamous by nature. Male-female pairs cohabit in the same burrow. A sexually mature fish will commonly starve if separated from its life partner.

This species is known to breed in captivity. Their mating habits are in fact quite unique. The female will first enter the burrow to deposit her eggs. She will then seal the male in the burrow for the eggs to be fertilized. The male will remain in the burrow for 2-3 days. During this time, the female will periodically open the burrow and release the male. The male may eat or the pair may perform routine maintenance in the burrow. Once the objective is achieved, the female will seal the male back in the burrow. Eventually, the male will permanently emerge from the burrow. The pair will then build another burrow or reopen a previously abandoned one. When the loan that acted as a nursery opens again, a single juvenile will emerge.