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Blackstripe Topminnow

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Fundulus notatus

Also known as: Black-striped Topminnow, Topminnow

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Description

The Blackstripe Topminnow (Fundulus notatus) is a small, freshwater fish belonging to the family Fundulidae. It is characterized by its slender body and a prominent black lateral stripe extending from the snout to the caudal fin base. This species is an important component of many aquatic ecosystems in its native range, serving as both a predator of small invertebrates and a prey item for larger fish and birds. It is known for its surface-dwelling habits, often found just beneath the water's surface.

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

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.

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.

Mouth Position

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

Body Shape

Its slender, somewhat flattened body is typical of topminnows.

Habitat

Water type
freshwater
Depth
Typically found in shallow waters, often less than 1 meter deep.
Environment
Prefers slow-moving or still waters of streams, rivers, oxbow lakes, ponds, and backwaters. Commonly found in areas with abundant aquatic vegetation, submerged logs, or overhanging banks that provide cover. Tolerant of a range of substrate types, including mud, sand, and gravel.
Geographic range
Native to the central United States, primarily within the Mississippi River basin. Its range extends from southern Wisconsin and Minnesota south to the Gulf Coast states (Louisiana, Mississippi, Alabama) and west into eastern Kansas, Oklahoma, and Texas. Eastward, it reaches into western Kentucky and Tennessee.

Aquarium Information

  • Care level: beginner
  • Temperament: peaceful
  • Diet: omnivore
  • Minimum tank size: 10 gallons
  • Temperature: 18-24°C (65-75°F)
  • pH level: 6.5-7.5
  • Hardness: 5-15 dGH
  • Compatibility: Compatible with other small, peaceful fish. Avoid housing with aggressive or fin-nipping species.
  • Special requirements: Requires a well-planted tank with some open swimming areas. A tight-fitting lid is essential as they are known jumpers. Surface feeding is common, so floating foods are beneficial.

Wild Information

  • Conservation status: least concern
  • Seasonality: Breeds primarily from late spring to early autumn, with peak activity in warmer months.
  • Market price: Low (primarily baitfish or aquarium trade)
  • Commercial importance: low
  • Taste: Not typically consumed due to small size.
  • Texture: Not typically consumed due to small size.
  • Nutritional value: Not typically consumed due to small size.

Key Facts

Surface Dwellerbehavior

Blackstripe Topminnows spend most of their time at or near the water's surface, feeding on insects and other small organisms that fall onto the water.

Mosquito Controlinteresting

Due to their diet of surface insects, including mosquito larvae, they play a beneficial role in controlling mosquito populations in their native habitats.

Sexual Dimorphismbehavior

Males in breeding condition develop more vibrant coloration, including iridescent blue or green hues, and their black stripe becomes more pronounced.

Egg Scatterersbehavior

They are egg-scattering spawners, typically laying eggs among aquatic vegetation or detritus, with no parental care.

Safety Information

Safe
  • Safety level: safe
  • Venomous: No
  • Edibility: not recommended
  • Handling notes: No specific handling precautions are required. They are small, harmless fish. Handle gently if caught for observation or relocation.

Similar Species

Northern Studfish

Fundulus catenatus

Lacks the prominent black lateral stripe; instead, males have vertical bars or rows of spots. Dorsal fin origin is typically anterior to or directly above the anal fin origin.

Starhead Topminnow

Fundulus dispar

Possesses a series of small, dark spots along the lateral line, often forming a broken stripe, rather than a solid black stripe. Also has a distinctive 'star' pattern on the head, which F. notatus lacks.

Plains Topminnow

Fundulus sciadicus

Generally has a less distinct or absent lateral stripe, and often exhibits a series of small, dark spots along the sides. Its range is more western than F. notatus.

Scientific Classification

Kingdom
Animalia
Phylum
Chordata
Class
Actinopterygii
Order
Cyprinodontiformes
Family
Fundulidae
Genus
Fundulus
Species
Fundulus notatus

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