Smallmouth Bass

Micropterus dolomieu, the Smallmouth Bass, is a prized sport fish and a formidable predator of cool, clear, rocky streams and lakes across eastern North America. It is distinguished from the Largemouth Bass by a jaw that does not extend behind the eye, distinctive vertical bars on bronze-green flanks, and the characteristic red iris. It prefers swift, cool, oxygen-rich water over gravel and rock substrates.

In the aquarium, Smallmouth Bass are impressive and active fish with a strong presence, but they demand significant resources: large volumes of well-oxygenated, cool water and regular live or meaty food offerings. Juveniles are easier to manage but grow quickly, and long-term commitment to appropriately sized housing is essential.

They are highly responsive to visual stimuli and will track movement outside the tank, making them engaging display animals. However, they are aggressive toward tankmates and should generally be kept as solitary specimens. Dedicated native predator enthusiasts with appropriate large cool-water systems will find them deeply rewarding.

Water: 10–25 °C, pH 6.5–8.0, moderate to hard, well-oxygenated; river-style current beneficial. Tank: 800 L minimum; large flat rocks, gravel substrate, open swimming lanes; cover for retreat. Feeding: Live fish, crayfish, large earthworms; can be trained to fresh cut fish and large pellets. Breeding: Gravel nest in spring; male guards vigorously — not practical in most home aquaria. Compatibility: Solitary; will eat any fish it can subdue — keep alone or with comparably sized robust species only.