How to Identify Diamond Killifish

To identify Diamond Killifish (Adinia xenica), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

The body is typically silvery to olive-brown dorsally, fading to a lighter, often yellowish or whitish ventral surface. Distinctive vertical bars (usually 8-12) are present on the flanks, which can be more prominent in males, especially during breeding. Males often display iridescent blue or green reflections, particularly on the operculum and fins, giving rise to the 'diamond' moniker. Females are generally duller.

Scale type

cycloid

Mouth position

superior

Distinctive features

Laterally compressed, somewhat diamond-shaped body, especially in mature individuals., Small, upturned mouth., Distinct vertical bars on the flanks., Iridescent blue/green sheen in males.

Dorsal fin

Single dorsal fin, originating anterior to the anal fin origin. Typically has 9-12 soft rays.

Tail fin

Rounded to slightly truncate caudal fin.

Pectoral fin

Small, rounded pectoral fins.

Distinctive fins

Pelvic fins are small and located abdominally. Anal fin has 10-13 soft rays.

Identification Tips

1. 1

   Body Shape

   Look for the distinctly compressed, somewhat diamond-shaped body, especially noticeable in adults. This is a key differentiator from many other killifish species which tend to be more cylindrical.

2. 2

   Coloration and Markings

   Observe the 8-12 dark vertical bars on the flanks. Males will often exhibit a striking iridescent blue or green sheen, particularly on the head and anterior body, which is less pronounced or absent in females.

3. 3

   Mouth Position

   Note the small, upturned mouth, indicating its surface-feeding habits.

4. 4

   Dorsal Fin Origin

   The dorsal fin originates anterior to the anal fin origin, a characteristic shared with other Fundulidae but useful in combination with other features.

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