How to Identify Australian Mudskipper

To identify Australian Mudskipper (Periophthalmus australis), look at these key features.

Physical Characteristics

Body shape

elongated

Coloration

Dorsal surface typically mottled brown, grey, or olive-green, providing camouflage against mud and mangrove roots. Ventral surface lighter, often whitish or pale grey. Fins may have darker bands or spots. Coloration can vary slightly based on habitat and mood.

Scale type

cycloid

Mouth position

terminal

Distinctive features

Large, bulbous, independently rotatable eyes positioned dorsally on the head, allowing for a wide field of vision above water., Strong, muscular pectoral fins that act as 'crutches' for terrestrial locomotion., Dorsal fins are prominent; the first dorsal fin is typically taller and more pointed, often with a dark margin., Ability to breathe through skin and buccal lining out of water., Possession of a gular fold that can hold water, keeping gills moist.

Dorsal fin

Two distinct dorsal fins. The first dorsal fin (D1) has 10-15 spines, is often tall and sail-like, especially in males during display. The second dorsal fin (D2) has 1 spine and 10-13 soft rays, is lower and longer.

Tail fin

Rounded to slightly emarginate caudal fin.

Pectoral fin

Large, muscular, and highly mobile, adapted for 'walking' on land. They have a fleshy base.

Distinctive fins

Pelvic fins are fused into a disc-like structure, often used for adhesion to surfaces or as an additional support during terrestrial movement.

Identification Tips

1. 1

   Eyes

   Look for large, protruding, independently movable eyes on top of the head, characteristic of mudskippers.

2. 2

   Pectoral Fins

   Observe the strong, muscular pectoral fins used for 'walking' on land, distinguishing them from typical fish fins.

3. 3

   Dorsal Fins

   Note the two distinct dorsal fins; the first is often taller and more pointed, especially in males.

4. 4

   Coloration

   Mottled brown/grey/olive coloration helps them blend into muddy environments.

5. 5

   Behavior

   Their amphibious nature, spending significant time out of water, is a key identifier.

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