Johnny Darter

The Johnny Darter is one of the most widespread darters in North America, found in a huge variety of clean-water habitats from small streams to large rivers. Its mottled brown-and-grey camouflage pattern provides near-perfect concealment on a sandy or gravelly substrate.

Breeding males develop a blackened head and intensified markings. Males select a small territory under flat stones where females deposit eggs, which the male then guards until hatching. This nest-guarding behaviour is fascinating to observe.

As one of the more adaptable darters, the Johnny Darter tolerates a wider range of conditions than many congeners, though it still requires cool, clean water and a meat-based diet.

Water: 8–20°C, pH 6.5–8.0, GH 5–15; clean, well-oxygenated water; gentle to moderate current. Tank: minimum 60 L, fine sand and gravel, flat stones for sheltering and nest sites. Feeding: carnivore — live/frozen bloodworm, daphnia, brine shrimp, small earthworm pieces. Breeding: male guards eggs under flat stone; remove other fish during breeding to reduce stress. Compatibility: peaceful; compatible with other small coolwater North American natives.