Smallmouth bass
Micropterus dolomieu
Also known asBronzeback · Smallie · Brown bass
Water parameters
Minimum tank: 400 L per individual at harvest size.
Feed and growth
- Feed protein
- 40% target
- Daily feed (warm)
- 1.20% of body weight
- Daily feed (cool)
- 0.60% of body weight
- Max density
- 30 g per litre
A 900 g adult eats about 10.8 g of feed per day at optimum. 10 fish at adult size: ~108 g daily.
Legality
Rules vary by jurisdiction and change over time. Verify with your local fisheries or wildlife authority before stocking.
| Jurisdiction | Status | Notes |
|---|---|---|
| California | permit required | verified 2026-05-13 |
| Texas | permit required | verified 2026-05-13 |
| European Union (bloc) | check local regulations | Introduced and locally invasive in several European countries, but could not confirm inclusion on the EU list of invasive alien species of Union concern (Reg 1143/2014) as of this check; member-state rules vary. verified 2026-05-29 |
Unlisted jurisdictions default to "check local regulations".
Origin and habitat
Native to central and eastern North America, through the St. Lawrence and Great Lakes, Hudson Bay (Red River) and Mississippi systems, from southern Quebec and Ontario west to North Dakota and south to northern Alabama and eastern Oklahoma. A member of the sunfish family Centrarchidae, it favours clear, cool rivers and lakes over rock or sand, holding stronger current and cooler water than largemouth bass. Most adults run about 40–50 cm and 2–3 kg, with a maximum near 69 cm and 5.4 kg. Smallmouth are among the most popular sport fish in North America, valued for their hard fight, and the flesh is white, firm and mild. Stocked for sport since the nineteenth century, the species has spread well beyond its native range across the US and into Europe, Africa and Asia, where it is often a damaging predator, notably on salmon and other native fish.
Climate and outdoor ponds
- Climate
- temperate (handles seasonal swings)
- USDA zones
- 4–9 (winter low around -34°C or warmer)
- Heating needed
- no
- Cooling needed
- no
Care notes
A cool-water predator cultured much like largemouth bass but tuned to cooler, clearer water. It does best around 18–24°C, a couple of degrees below largemouth, within a tolerance of roughly 8–29°C, and spawns once water passes about 15–16°C. In culture, pellet-trained fish reach perhaps 300–600 g in 18 to 24 months on high-protein feed of 42 to 48 percent; like largemouth, they must be weaned onto pellets as small fingerlings, and fish that have learned to chase live prey are very hard to convert, so buy pellet-trained stock. Stock lightly, around {density:8}-{density:12}, since smallmouth are active swimmers that stress in tight confinement, and grade strictly because size classes will cannibalise. They need cleaner water than largemouth, with dissolved oxygen above 5 mg/L and low ammonia, which actually suits a well-filtered aquaponics loop. Fingerlings come from bass hatcheries, though less commonly than largemouth, and culture generally needs a state aquaculture permit. In parts of Europe and elsewhere the fish is treated as an invasive pest, so check local rules before stocking. For cool-water aquaponics in the northern US, it is a premium choice.