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The Dusky-gilled Mudskipper was formerly synonymized with Periophthalmus novemradiatus, leading to some outdated signboards in our parks.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.

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.

Gold-spotted Mudskipper (Periophthalmus chrysospilos)

Gold-spotted Mudskipper (Periophthalmus chrysospilos)

A male Gold-spotted Mudskipper identified by the elongated first spine of the first dorsal fin. This was seen in the intertidal zone of Bukit Chermin Boardwalk.

Family: Oxudercidae (Subfamily Oxudercinae - Mudskippers)

Species Name: Periophthalmus chrysospilos
Common Name(s): Gold-spotted Mudskipper

Presence in Singapore: Native
Habitat: Coastal: Intertidal zones such as sandy beaches and mudflats
Conservation status: Vulnerable (Red Data Book 3)

The Gold-spotted Mudskipper is an average-sized species, reaching around 10cm long usually. This species is easily identified by the orange-gold spots that cover the sides of its body, resulting in its common name. It also has bright orange dorsal fins that stand out from the other mudskippers in Singapore. In the males, the first dorsal spine is very elongated, which is a feature not seen in its relatives under the same genus locally.

The Gold-spotted Mudskipper is abundant in open intertidal zones along the coast such as mudflats and sandy beaches. It is rarely seen inside mangrove forests where its relatives are common. During high tide, they go further up the beach or wait it out on mangrove roots and other elevated surfaces.

A Gold-spotted Mudskipper braving the high tide and strong winds while clinging to a mangrove sapling.

This species is omnivorous and appears to have different feeding styles. It hunts smaller invertebrates on-sight but also grazes on surfaces for algae and microorganisms. We have observed this species grazing on the rocks they're sitting on every time the wave crashes into it.

Territorial display of the Gold-spotted Mudskipper.

References

• FishBase. Periophthalmus chrysospilos Bleeker, 1853 – Gold-spotted Mudskipper. Retrieved from https://www.fishbase.se/summary/Periophthalmus-chrysospilos.html
• 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.

Silver-lined Mudskipper (Periophthalmus argentilineatus)

Silver-lined Mudskipper (Periophthalmus argentilineatus)

A Silverlined Mudskipper seen on St John's Island, where it is rather plentiful. 

Family: Oxudercidae (Subfamily Oxudercinae - Mudskippers)

Species Name: Periophthalmus argentilineatus
Common Name(s): Silver-lined Mudskipper, Barred Mudskipper

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

This is an abundant species seen in Singapore from both inside mangrove forests to even sandy shores that at least meet a patch of mangroves (indicating some mud). The Silver-lined Mudskipper is an average-sized mudskipper, reaching just under 10cm at max. It is named after the silver stripes on the sides of its body but other species can have similar patterns as well. Thus, a shot of the raised dorsal fins can help separate it from similar-looking species in the region. The first dorsal fin is red with a black and white margin running from the top to the back of the fin, while the red area has many spots. 

A Silver-lined Mudskipper flaring its dorsal fins to another of its kind. (Photograph by: Lumin Ong)

This species is an opportunistic carnivore, feeding on whatever could feed in its mouth such as small invertebrates.

A Silver-lined Mudskipper feeding on what appears to be a polychaete worm that it dug out from the mud.

Although not recorded in Singapore (so far), Periophthalmus kalolo frequently appears alongside this species elsewhere and look pretty much the same. A ventral view of the pelvic fin is currently the best way to differentiate them (Polgar, 2014). 

References

• Polgar, G. Gobiidae: Oxudercinae – Periophthalmus argentilineatus Valenciennes, 1837. Retrieved from http://www.mudskipper.it/SpeciesPages/arge.html
• FishBase. Periophthalmus argentilineatus (Valenciennes, 1837) – Barred Mudskipper. Retrieved from https://www.fishbase.se/summary/Periophthalmus-argentilineatus
• 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.

Yellow-spotted Mudskipper (Periophthalmus walailakae)

Yellow-spotted Mudskipper (Periophthalmus walailakae)

A Yellowspotted Mudskipper seen in Berlayer Creek. (Photograph by: Lumin Ong)

Family: Oxudercidae (Subfamily Oxudercinae - Mudskippers)

Species Name: Periophthalmus walailakae
Common Name(s): Yellow-spotted Mudskipper, Walailak's Mudskipper

Presence in Singapore: Native
Habitat: Coastal: Mangrove forests
Conservation status: Vulnerable (Red Data Book 3)

This is a large mudskipper species for its genus, reaching nearly 13cm in length at max. It is relatively common in our muddy mangrove forests but can also be seen further out along the shore, sometimes in sandier habitats. The top half of its body has several saddle-like stripes while its flanks are covered with yellow spots, giving it the common name it's known by locally. Its first dorsal fin is un-patterned, being red with black and white margins along the top down to the back. 

The Yellow-spotted Mudskipper is an opportunistic carnivore, preying on small crustaceans and other invertebrates. Its burrows are usually further back in the mangroves in mud and it doesn't seem to stray far from the shelter of the mangrove forests.

A Yellow-spotted Mudskipper showing a bit of its first dorsal fin. (Photograph by: Lumin Ong)

References

• FishBase. Periophthalmus walailakae. Country species summary for Singapore. Retrieved from https://www.fishbase.se/Country/CountrySpeciesSummary.php?c_code=764&id=61443
• Polgar, G. Gobiidae: Oxudercinae – Periophthalmus walailakae Darumas & Tantichodok, 2002. Retrieved from http://www.mudskipper.it/SpeciesPages/wala.html
• 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.

Giant Mudskipper (Periophthalmodon schlosseri)

Giant Mudskipper (Periophthalmodon schlosseri)

A Giant Mudskipper emerging from its burrow in Pasir Ris Park's mangroves. (Photograph by: Lumin Ong)

Family: Oxudercidae (Subfamily Oxudercinae - Mudskippers)

Species Name: Periophthalmodon schlosseri
Common Name(s): Giant Mudskipper

Presence in Singapore: Native
Habitat: Coastal: muddy mangrove swamps and mudflats.
Conservation status: Least Concern (Red Data Book 3)

This is the largest mudskipper seen in Singapore and one of the largest in the entire world for it can reach almost 30cm in length. Due to its sheer size and abundance in the right habitats, it is also the most often seen mudskipper in Singapore as it is hard to miss. It is easily recognizable via a dark, horizontal stripe that runs along the sides of its body starting from the eyes. It is also peppered with light blue spots towards the bottom half of its body.

The Giant Mudskipper is carnivorous, possessing impressive fangs for its kind. It preys on smaller fishes, crustaceans and have even been known to eat reptiles such as snakes. They have been observed digging for burrowing prey such as eels. This highly territorial species chases other individuals that get too close.

The Giant Mudskipper inhabits mangrove swamps where the substrate is muddy and can even be found further out on open mudflats. They dig large burrows marked by a round pool visible at low tide, where the mudskipper usually sits in. In mated pairs, both the male and female help to maintain the burrow These pools are usually shelter to smaller mangrove fishes such as their goby cousins during low tide (see Ong & Tay, 2024), which are often too small for the mudskipper to bother about. They can be seen waiting out the high tide on mangrove roots and other elevated surfaces. 

A Giant Mudskipper hard at work digging in Sungei Buloh Wetland Reserve. (Photograph by: Lumin Ong)

A young Giant Mudskipper taking shelter on a rock during high tide. (Photograph by: Lumin Ong)

References

• FishBase. Periophthalmodon schlosseri (Pallas, 1770) – Giant Mudskipper. Retrieved from https://www.fishbase.se/summary/Periophthalmodon-schlosseri
• 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.
• Ong JXL & Tay JX (2024) Biodiversity Record: Fish fauna of a mangrove tide pool at Sungei Buloh. Nature in Singapore, 17: e2024056. DOI: 10.26107/NIS-2024-0056

Mangrove Jack (Lutjanus argentimaculatus)

  Mangrove Jack (Lutjanus argentimaculatus)

A large individual found in Pasir Ris Park's mangroves which has seen some fighting with anglers. (Photograph by: Lumin Ong)

Family: Lutjanidae
Species Name: Lutjanus argentimaculatus
Common Name(s): Mangrove Jack, Mangrove Red Snapper

Presence in Singapore: Native
Habitat: Based on age - Adults: offshore coral reefs, Juveniles: Estuaries and rivers.
Conservation status: Near Threatened (Red Data Book 3)

The Mangrove Jack is a name known to many people as a game fish, food and even pets. This euryhaline fish covers a wide range of habitats depending on its age. Younger adults and juveniles inhabit inland waters such as estuaries and even freshwater streams, while adults move to deeper waters offshore over coral reefs. 

Growing up to a maximum size of 1.5 meters, this is a formidable predator in the ecosystems it occurs on whatever fits into its mouth. Like its relatives, it possesses sizable fangs that helps in snagging unsuspecting prey. It is an ambush predator, carefully inspecting and sneaking around shelters such as mangrove roots for its prey before catching them with a burst of speed.

As mentioned earlier, the Mangrove Jack is a popular commercial fish that is caught and farmed for its meat. It is also famous among fishermen for its burst of speed upon getting hooked.

A small Mangrove Jack found in full saltwater around Sentosa. (Photograph by: Lumin Ong)

References

• FishBase. Lutjanus argentimaculatus (Forsskål, 1775) – Mangrove Red Snapper. Retrieved from https://www.fishbase.se/summary/lutjanus-argentimaculatus.html.
• 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.