How to Identify Australian Rainbowfish

To identify Australian Rainbowfish (Melanotaenia australis), look at these key features.

Physical Characteristics

Body shape

elongated

Coloration

Males exhibit iridescent scales with shades of blue, green, yellow, and red, often with a prominent dark lateral stripe running from the snout to the caudal fin base. The intensity of colors varies with mood, health, and breeding condition. Females are generally duller in coloration, often silvery-brown with a less distinct lateral stripe. Fins can be translucent to yellowish or reddish.

Scale type

cycloid

Mouth position

terminal

Distinctive features

Two distinct dorsal fins, the first being smaller and spiny, the second larger and soft-rayed., Laterally compressed body., Relatively large eyes., Terminal mouth.

Dorsal fin

Two dorsal fins: D1 (spiny) with 4-7 spines; D2 (soft-rayed) with 1 spine and 8-14 soft rays. The second dorsal fin is typically larger and more elongated in males.

Tail fin

Forked caudal fin, often with a reddish or yellowish hue.

Pectoral fin

Small, clear to yellowish pectoral fins.

Distinctive fins

Pelvic fins are small and located abdominally. Anal fin is long, originating just behind the pectoral fins, with 1 spine and 15-22 soft rays.

Identification Tips

1. 1

   Body Shape and Size

   Elongated, laterally compressed body, typically reaching 8-10 cm (3-4 inches) in length, though some individuals can grow up to 12 cm (5 inches).

2. 2

   Coloration

   Males display vibrant iridescent colors (blue, green, yellow, red) with a prominent dark lateral stripe. Females are duller, silvery-brown.

3. 3

   Dorsal Fins

   Presence of two distinct dorsal fins, with the second dorsal fin being noticeably larger and more pointed in mature males.

4. 4

   Lateral Line

   A distinct lateral line is present, though sometimes interrupted.

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