Slender Mudskipper (Periophthalmus gracilis)

 Slender Mudskipper (Periophthalmus gracilis)

A Slender Mudskipper seen on the sandy shores of St John's Island.

Family: Oxudercidae (Subfamily Oxudercinae - Mudskippers)

Species Name: Periophthalmus gracilis
Common Name(s): Slender Mudskipper, Graceful Mudskipper

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

The Slender Mudskipper is a small species, reaching a maximum recorded length of 4.5cm. This species usually has thin, silver stripes and slanting black bands on the side of its body, making it easy to confuse with the Silver-lined Mudskipper and Dusky-gilled Mudskipper. The best way to identify this mudskipper is to look at the gap between its two dorsal fins, which are very far part compared to its relatives. The first dorsal fin is also small and rectangular, with dark patterns and blue margins over a lighter colour base compared to the red base of the two earlier mentioned species.

This is a common species, being seen in the back mangroves down to open intertidal zones such as mudflats. It is often seen alongside its relatives listed in this blog as well. Being an opportunistic carnivore, it preys on small invertebrates. 

A Slender Mudskipper caught via hand-line for dorsal fin inspection. (Photograph by: Jiayuan Lin)

References

• FishBase. Periophthalmus gracilis Eggert, 1935 – Graceful (Slender) Mudskipper. Retrieved from https://www.fishbase.se/summary/Periophthalmus-gracilis
• 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.