How to Identify Dwarf Flathead Gudgeon

To identify Dwarf Flathead Gudgeon (Philypnodon macrostomus), look at these key features.

Physical Characteristics

Body shape

elongated

Coloration

Highly variable, typically mottled brown, grey, or olive-green with darker blotches and spots, providing excellent camouflage. The ventral surface is usually paler. Fins often have faint banding or spotting.

Scale type

ctenoid

Mouth position

superior

Distinctive features

Flattened head profile, particularly dorsally., Large, upward-pointing mouth with a prominent lower jaw., Two distinct dorsal fins, the first spiny and the second soft-rayed., Large pectoral fins., Small, embedded scales.

Dorsal fin

Two dorsal fins; the first with 6-8 spines, the second with 1 spine and 7-10 soft rays. The first dorsal fin is typically lower than the second.

Tail fin

Rounded to slightly emarginate caudal fin.

Pectoral fin

Large and fan-like, typically with 15-18 rays.

Distinctive fins

Pelvic fins are separate (not fused into a disc as in true gobies), located thoracically, with 1 spine and 5 soft rays.

Identification Tips

1. 1

   Head Shape

   Look for the distinctly flattened head, which is broader than it is deep, giving it a 'flathead' appearance.

2. 2

   Mouth Size and Position

   Observe the relatively large, upward-pointing mouth with a prominent lower jaw, indicative of its predatory nature.

3. 3

   Dorsal Fins

   Note the presence of two separate dorsal fins. The first is spiny and typically lower than the second, soft-rayed dorsal fin.

4. 4

   Pelvic Fins

   Unlike true gobies, the pelvic fins are separate and not fused into a suction disc. This is a key distinguishing feature from many other small, bottom-dwelling fish.

5. 5

   Coloration and Pattern

   Its mottled, cryptic coloration helps it blend with the substrate. Patterns of dark blotches and spots are common.

6. 6

   Size

   Adults typically reach a maximum standard length of about 6-8 cm, making them one of the smaller gudgeon species.

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