How to Identify Blackstripe Topminnow

To identify Blackstripe Topminnow (Fundulus notatus), look at these key features.

Physical Characteristics

Body shape

elongated

Coloration

The body is generally olive-brown to yellowish-tan dorsally, fading to a lighter, silvery-white ventrally. The most distinctive feature is a prominent, dark black lateral stripe that runs from the tip of the snout, through the eye, and along the entire length of the body to the base of the caudal fin. Males in breeding condition may exhibit iridescent blue or green hues on their flanks and fins, and the black stripe may intensify.

Scale type

cycloid

Mouth position

superior

Distinctive features

Prominent black lateral stripe from snout to caudal fin base., Dorsal fin origin posterior to anal fin origin., Flattened head and dorsal surface, adapted for surface dwelling.

Dorsal fin

Small, located far back on the body, originating posterior to the origin of the anal fin. Typically has 8-10 rays.

Tail fin

Rounded to slightly truncate.

Pectoral fin

Relatively small and rounded.

Distinctive fins

Pelvic fins are small and located abdominally. Anal fin is relatively large, with 10-13 rays, and its origin is anterior to the dorsal fin origin.

Identification Tips

1. 1

   Lateral Stripe

   Look for the distinct, unbroken black stripe running from the snout through the eye to the caudal fin base. This is the most reliable identifying feature.

2. 2

   Fin Placement

   Note that the dorsal fin originates behind the origin of the anal fin. This is a key characteristic for distinguishing it from some other Fundulus species.

3. 3

   Mouth Position

   The upturned mouth (superior) is indicative of its surface-feeding habits.

4. 4

   Body Shape

   Its slender, somewhat flattened body is typical of topminnows.

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