How to Identify American Flagfish

To identify American Flagfish (Jordanella floridae), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Males are strikingly colored with iridescent blue-green bodies, red fins, and a prominent dark spot on the flank, often bordered by iridescent scales. They also exhibit vertical red and blue stripes, resembling a flag. Females are duller, typically olive-brown with a less distinct dark spot and less vibrant fin coloration. Juveniles resemble females.

Scale type

cycloid

Mouth position

superior

Distinctive features

Prominent dark spot on the flank, often with iridescent borders., Vertical red and blue stripes on males, resembling a flag., Rounded caudal fin., Small, upturned mouth.

Dorsal fin

Single dorsal fin, set relatively far back on the body. Males have a larger, more pointed dorsal fin than females.

Tail fin

Rounded caudal fin.

Pectoral fin

Small, rounded pectoral fins.

Distinctive fins

Anal fin in males is larger and more pointed than in females, often with red coloration.

Identification Tips

1. 1

   Size

   Adults typically reach 5-6 cm (2-2.5 inches) in total length.

2. 2

   Coloration (Males)

   Look for the vibrant blue-green body, red fins, and distinct vertical red and blue stripes, especially when breeding. The prominent dark spot on the flank is a key identifier.

3. 3

   Coloration (Females)

   Females are less colorful, generally olive-brown with a less pronounced dark spot and duller fins.

4. 4

   Body Shape

   Laterally compressed body with a relatively deep profile for a killifish.

5. 5

   Mouth

   Small, upturned mouth, indicative of a surface feeder.

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