How to Identify McCulloch's Rainbowfish

To identify McCulloch's Rainbowfish (Melanotaenia maccullochi), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Males display iridescent colors ranging from silver-blue to olive-green on the body, often with a prominent dark lateral stripe running from the operculum to the caudal fin base. Fins can be yellow, orange, or reddish, sometimes with dark margins. Females are generally duller in coloration, typically silvery-brown with a less distinct lateral stripe and clear or yellowish fins. Color intensity can vary significantly depending on geographic origin, mood, and health.

Scale type

cycloid

Mouth position

superior

Distinctive features

Small size, typically reaching 5-7 cm (2-2.8 inches) in total length., Prominent dark lateral stripe., Sexual dimorphism in coloration and fin elongation., Two distinct dorsal fins, with the first being much smaller than the second.

Dorsal fin

Two dorsal fins; the first is small with 3-6 spines, and the second is larger with 1 spine and 8-12 soft rays. In mature males, the second dorsal fin is often elongated and pointed.

Tail fin

Forked caudal fin.

Pectoral fin

Paired pectoral fins, typically clear or yellowish.

Distinctive fins

Anal fin with 1 spine and 15-20 soft rays, often elongated in mature males, mirroring the shape of the second dorsal fin.

Identification Tips

1. 1

   Size

   One of the smaller rainbowfish species, rarely exceeding 7 cm (2.8 inches).

2. 2

   Lateral Stripe

   Presence of a distinct dark, often black, lateral stripe running along the mid-body.

3. 3

   Fin Shape (Males)

   Mature males have noticeably elongated and pointed second dorsal and anal fins.

4. 4

   Coloration

   Iridescent body colors, often with yellow, orange, or reddish fins, especially in males.

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