Dusky-gilled Mudskipper (Periophthalmus variabilis)

Dusky-gilled Mudskipper (Periophthalmus variabilis)

A small Dusky-gilled Mudskipper on the sandy shores of St John's Island.

Family: Oxudercidae (Subfamily Oxudercinae - Mudskippers)

Species Name: Periophthalmus variabilis
Common Name(s): Dusky-gilled Mudskipper

Presence in Singapore: Native
Habitat: Coastal: Mangrove forests down to lower intertidal zones.
Conservation status: Vulnerable (Red Data Book 3)

The Dusky-gilled Mudskipper is a small species, reaching a maximum total length of 7cm. This species is identified by its variable black blotches that usually fade towards the bottom. It also has tiny whitish-blue spots across the body. Its red dorsal fins are similar to the Silver-lined Mudskipper but in the first dorsal fin, the black margin curves down to the base and it lacks the many white specks. 

The Dusky-gilled Mudskipper was formerly synonymized with Periophthalmus novemradiatus, leading to some outdated signboards in our parks. It is now a recognized separate species from its relative further north. 

This species shares a similar habitat range to most of its relatives, being abundant in back mangroves all the way down to intertidal zones. It doesn't seem to stray far from the shelter of mangroves however unlike the Gold-spotted Mudskipper. It is an opportunistic carnivore that feeds on small invertebrates.

Territorial display of a Dusky-gilled Mudskipper with dorsal fins in full view.

References

• FishBase. Periophthalmus variabilis Eggert, 1935 – (mudskipper). Retrieved from https://fishbase.se/summary/65362
• Lim, K.K.P. & Low, J.K.Y. 1998. A Guide to Common Marine Fishes of Singapore. Singapore Science Centre, 163 pp. ISBN 981-00-9904-5.
• National Parks Board (NParks). Marine Fishes. Retrieved from https://www.nparks.gov.sg/nature/species-list/marine-fishes.