• Family: Fundulidae (Topminnows)
• Other Names: None
• Ohio Status: Introduced
• Adult Size: Typically 3-4 inches, can reach 6 inches.
• Typical Foods: Aqautic insect larvae and other invertebrates.
Northern studfish have a light brown back with a short gold streak down the center of their back just in front of the dorsal fin. The dorsal and anal fins are set far back on the body like other topminnows. Also like other topminnows, the dorsal and anal fins of females are smaller and rounded compared to the long pointed fins of males. Their sides are silver or blue in color with redish brown spots on the sides of their head and many redish brown horizontal lines along their sides. On breeding males these lines and spots are a brilliant red over a vivid light blue background. Breeding males also have a bright orange margin to their tail followed by an almost black band.
Habitat and Habits
Northern studfish are found along the edge of pools and riffles in a wide size range of streams. They tend to stay in shallow water often only a couple of inches deep. They prefer clear waters with clean sand and gravel substrates. This species was introduced to Ohio and was first discovered in 1995 in Massies Creek which is a tributary to the Little Miami River. Since then they have spread through out much of the Little Miami River system and have recently been found in a small Belmont county creek in South East Ohio. It is thought that the Little Miami population was introduced by someone who released unused bait or individuals from a personal aquarium that were no longer wanted. This is one likely example of the proliferation and spread of non-native fishes through illegal release or stocking. Anglers are reminded that unused bait or aquarium fishes should be disposed humanely and not released alive to public waters. Ohio Administrative Code (OAC) 1501:31-13-01(7) states that, “It shall be unlawful for any person to release any fish or aquatic insect into the waters of the state, or waters under control of the Division of Wildlife without first obtaining permission from the Chief of the Division of Wildlife.”
Reproduction and Care of the Young
Northern studfish spawn in shallow water along the edge of streams. Unlike most Fundulus species (topminnows) they spawn on clean gravel substrate rather than on plants. It has been reported that they may occasionally use the nests of longear or other sunfish species as spawning sites. No parental care is given to the eggs or young.