A popular North American freshwater gamefish sometimes kept by dedicated hobbyists in massive coldwater aquariums. They are powerful, highly active apex predators that require exceptional filtration, high water flow, and massive tank footprints. They will consume any tank mate that can fit into their large mouths.
Smallmouth Bass At a Glance
Smallmouth Bass Tank Requirements
Will Smallmouth Bass fit in your tank?
Care guides tell you what Smallmouth Bass needs, the next question is whether your tank can safely provide it. Test Smallmouth Bass against your tank size, maintenance needs, and the fish you already keep before you buy.
Smallmouth Bass Water Parameters
Smallmouth Bass Temperament & Compatibility
Smallmouth Bass Varieties
Each variety inherits the species defaults above. Only differences are highlighted.
Standard Adult
Fully grown adult. Requires exceptional filtration and footprint due to their high activity levels and massive predatory bioload.
Same care requirements as the base species
Also known as: Adult Smallmouth, Wild Type
Juvenile (Grow-out)
Young Smallmouth Bass. Voracious eaters that grow incredibly fast in their first year. While they can temporarily be housed in smaller tanks, they will rapidly outgrow them.
Differs in 4 traits from base species
Also known as: Baby Smallie, Fingerling
Smallmouth Bass Care Guide Summary
The Smallmouth Bass, scientifically known as Micropterus dolomieu, belongs to the Other family group. Adults reach a maximum size of approximately 45 cm and have a fusiform body shape with a moderate growth rate. Classified as aggressive, this species primarily occupies the mid-level and bottom zones of the aquarium and produces a extreme level of biological waste.
To thrive, the Smallmouth Bass requires a freshwater only aquarium with a minimum volume of 680 litres and a tank length of at least 180 cm. Water temperature should be maintained between 15°C and 25°C, with a pH range of 6.5–8 and a general hardness of 5–20 dGH. A high water flow is preferred.
Due to its specialist needs, the Smallmouth Bass is best suited for fishkeepers who can provide a carefully planned setup. This species is available in 2 varieties: Standard Adult and Juvenile (Grow-out). Each may differ slightly in size, temperament, or care needs, so it is worth checking the specific requirements of the variety you plan to keep.
Smallmouth Bass Habitat Setup
When setting up an aquarium for the Smallmouth Bass, a high water flow best suits their natural preferences. Because this species occupies the mid-level and bottom zones, the aquarium layout should prioritise open swimming space in the centre of the tank for free movement and sufficient floor space with hiding spots among rocks, wood, or dense planting. Useful additions include smooth gravel or rounded substrate to protect their sensitive barbels and driftwood, which can serve as both a hiding place and a dietary supplement. Keepers should note that a tight-fitting lid is essential, as this species is a known jumper.
Smallmouth Bass Compatibility Notes
Classified as aggressive, the Smallmouth Bass is adaptable and can be kept singly or in a small group, offering flexibility when planning a community tank. When choosing tankmates, any fish small enough to fit in its mouth will likely be eaten, territorial behaviour may cause issues if hiding spots or floor space are limited, shy or slow-feeding tankmates may be outcompeted at feeding time, and their energetic swimming style may stress more sedentary or timid species. Selecting tankmates that favour different water layers from the mid-level and bottom zones can help reduce competition and territorial overlap.
Who Smallmouth Bass Is Actually For
Smallmouth Bass is best for a fishkeeper who expects a species with attitude and plans the tank around that behavior and can provide someone who understands its individual space requirements. It makes the most sense for a hobbyist who will actually build around its needs, especially smooth gravel.
The most common mistake is buying Smallmouth Bass for looks first and only later discovering how its adult size, behavior, or bioload changes the whole tank plan. Another frequent problem is forcing it into an over-busy community when it would do better with more room or more deliberate tankmate choices.
Smallmouth Bass Recommended Tank Sizes
Standard aquarium sizes that meet the minimum volume and length requirements for Smallmouth Bass.
Smallmouth Bass Feeding & Diet Considerations
The Smallmouth Bass is a predatory species that will readily consume small fish, so nano or bite-sized tankmates should be avoided and is an aggressive eater that may prevent timid tankmates from getting enough food, so target feeding or simultaneous feeding at opposite ends of the tank can help.
Frequently Asked Questions About Smallmouth Bass
How big does Smallmouth Bass get?
Smallmouth Bass (Micropterus dolomieu) typically reaches a maximum adult size of approximately 45 cm. They have a fusiform body shape and a moderate growth rate.
What tank size does Smallmouth Bass need?
A minimum aquarium volume of 680 litres and a tank length of at least 180 cm are recommended for Smallmouth Bass. This ensures enough swimming space and helps maintain stable water conditions.
What water parameters does Smallmouth Bass need?
Smallmouth Bass thrives in freshwater only conditions with a temperature range of 15–25°C, a pH between 6.5 and 8, and a general hardness of 5–20 dGH. A high water flow is preferred.
Is Smallmouth Bass peaceful or aggressive?
Smallmouth Bass is classified as aggressive with an aggression score of 7 out of 10. Careful tankmate selection is essential to avoid conflict.
Can Smallmouth Bass live alone?
Yes, Smallmouth Bass can be kept singly or in a group. They are flexible and adapt well to both setups.
Does Smallmouth Bass have any special tank requirements?
Yes. Smallmouth Bass benefits from smooth gravel (sensitive barbels) and driftwood (digestion/hiding) in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.
Does Smallmouth Bass need a lid on the tank?
Yes. Smallmouth Bass is a known jumper, and a tight-fitting lid or cover is essential to prevent escape. Even a small gap can be enough for a determined fish to leap out.
Useful setup supplies
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Guidarium Editorial Desk
Reviewed against Guidarium care, stocking, and compatibility standards. Read the editorial policy.
- Last reviewed
- May 11, 2026
- Last updated
- May 11, 2026
- Issues or corrections?
- Contact the editorial team
Plants That Suit Smallmouth Bass
These plants pair well with Smallmouth Bass based on shared water preferences, layout fit, and how likely they are to hold up in the same aquarium.
African Water Fern
Bolbitis heudelotii
Boivin's Aponogeton
Aponogeton boivinianus
Capuron's Aponogeton
Aponogeton capuronii
Madagascar Lace Plant
Aponogeton madagascariensis
African Onion Plant
Crinum calamistratum
Afzel's Anubias
Anubias afzelii
Fish Similar to Smallmouth Bass
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Yellow Perch
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Bumblebee Goby (Brackish)
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Rainbow Shark
Epalzeorhynchos frenatum
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Scarlet Badis
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