How to Identify Emperor Gudgeon

To identify Emperor Gudgeon (Hypseleotris compressa), look at these key features.

Physical Characteristics

Body shape

elongated

Coloration

Males are typically more brightly colored, especially during breeding, displaying iridescent blues, reds, and oranges on their fins and body. Females are generally duller, with a more subdued silvery-brown to olive coloration. Both sexes often have a series of faint horizontal stripes or blotches along their flanks. The caudal fin often has a reddish hue, particularly in males.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Two distinct dorsal fins, the first spiny and the second soft-rayed., Large, prominent eyes., Sexual dimorphism, with males exhibiting brighter colors and elongated fins during breeding., Often a reddish tint to the caudal fin.

Dorsal fin

Two dorsal fins; the first with 6-8 spines, the second with 1 spine and 8-10 soft rays. The first dorsal fin is often taller in males.

Tail fin

Rounded to slightly emarginate caudal fin, often with a reddish hue.

Pectoral fin

Large and rounded, typically with 13-15 rays.

Distinctive fins

Pelvic fins are separate and located beneath the pectoral fins, characteristic of gudgeons.

Identification Tips

1. 1

   Coloration

   Look for the vibrant iridescent blues, reds, and oranges in males, especially during breeding. Females are more subdued but may still show faint patterns.

2. 2

   Fin Structure

   Observe the two distinct dorsal fins and the rounded to slightly emarginate caudal fin, often with a reddish tint.

3. 3

   Body Shape

   Note the elongated, somewhat compressed body typical of gudgeons.

4. 4

   Size

   Adults typically reach 5-7 cm (2-2.8 inches) in length, with a maximum recorded size of about 10 cm (4 inches).

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