How to Identify Banded Killifish

To identify Banded Killifish (Fundulus diaphanus), look at these key features.

Physical Characteristics

Body shape

elongated

Coloration

Dorsal surface is typically olive-green to brownish, fading to silvery-white on the belly. Males exhibit 12-20 dark, narrow vertical bands along their sides, which are more pronounced during breeding. Females have fewer, fainter bands or may appear mottled. Fins are generally translucent, sometimes with a yellowish tint.

Scale type

cycloid

Mouth position

superior

Distinctive features

Elongated, somewhat flattened body, Flattened head with a superior mouth, Distinctive vertical bands, especially on males, Small, rounded caudal fin

Dorsal fin

Single, short-based dorsal fin located posterior to the anal fin origin, typically with 10-13 rays.

Tail fin

Rounded to slightly emarginate caudal fin.

Pectoral fin

Moderately sized, rounded pectoral fins.

Distinctive fins

Anal fin is similar in shape and size to the dorsal fin, with 10-13 rays. Pelvic fins are small and located abdominally.

Identification Tips

1. 1

   Body Shape and Size

   Look for a slender, elongated body, typically growing to 7-10 cm (3-4 inches) in length, with a maximum recorded size of about 13 cm (5 inches).

2. 2

   Head and Mouth

   Observe the flattened head and the distinctly superior mouth, meaning the lower jaw protrudes beyond the upper jaw, adapted for surface feeding.

3. 3

   Banding Pattern

   Note the vertical bands on the sides. Males have more numerous (12-20), darker, and more distinct bands, especially during the breeding season. Females have fewer, fainter, or mottled bands.

4. 4

   Fin Placement

   The dorsal fin is positioned relatively far back on the body, originating behind the origin of the anal fin.

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