A robust North American native fish commonly known as the 'Shellcracker' due to its specialized pharyngeal teeth used to crush snails and mollusks. They are a temperate (coldwater) species that makes an excellent subject for a large native unheated aquarium. They are semi-aggressive, territorial, and will consume any tank mate small enough to fit in their mouths.
Redear Sunfish At a Glance
Redear Sunfish Tank Requirements
Will Redear Sunfish fit in your tank?
Care guides tell you what Redear Sunfish needs, the next question is whether your tank can safely provide it. Test Redear Sunfish against your tank size, maintenance needs, and the fish you already keep before you buy.
Redear Sunfish Water Parameters
Redear Sunfish Temperament & Compatibility
Redear Sunfish Varieties
Each variety inherits the species defaults above. Only differences are highlighted.
Standard
The fully grown adult form. Males feature a bright cherry-red edge on the opercular (ear) flap, while females have a lighter orange edge. Very efficient at eradicating snail populations.
Same care requirements as the base species
Also known as: Adult
Juvenile (Grow-out)
Young Redear Sunfish. Can be kept in a smaller grow-out tank but will grow rapidly on a high-protein diet and require a major tank upgrade as they approach 20cm.
Differs in 5 traits from base species
Also known as: Baby, Fingerling
Redear Sunfish Care Guide Summary
The Redear Sunfish, scientifically known as Lepomis microlophus, belongs to the Other family group. Adults reach a maximum size of approximately 25 cm and have a compressed body shape with a moderate growth rate. Classified as semi-aggressive, this species primarily occupies the mid-level and bottom zones of the aquarium and produces a high level of biological waste.
To thrive, the Redear Sunfish requires a freshwater only aquarium with a minimum volume of 280 litres and a tank length of at least 120 cm. Water temperature should be maintained between 10°C and 26°C, with a pH range of 6.5–8.5 and a general hardness of 8–20 dGH. A low water flow is preferred.
The Redear Sunfish is a rewarding species to keep, provided its core environmental needs are met. This species is available in 2 varieties: Standard 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.
Redear Sunfish Habitat Setup
When setting up an aquarium for the Redear Sunfish, a low 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 a sand substrate to accommodate their sifting behaviour and shells for breeding and shelter. Keepers should note that expect substrate disturbance, so lightweight décor should be secured.
Redear Sunfish Compatibility Notes
Classified as semi-aggressive, the Redear Sunfish 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, ornamental shrimp are not safe companions, snails will be treated as food rather than tankmates, and territorial behaviour may cause issues if hiding spots or floor space are limited. Selecting tankmates that favour different water layers from the mid-level and bottom zones can help reduce competition and territorial overlap.
Who Redear Sunfish Is Actually For
Redear Sunfish is best for a fishkeeper who wants a species that can settle into a calmer community setup 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 sand.
The most common mistake is treating Redear Sunfish like any other community fish and skipping the soft sand it needs to forage safely. Another frequent problem is forcing it into an over-busy community when it would do better with more room or more deliberate tankmate choices.
Redear Sunfish Recommended Tank Sizes
Standard aquarium sizes that meet the minimum volume and length requirements for Redear Sunfish.
75 Gallon Standard
90 Gallon Standard
125 Gallon Standard
150 Gallon High
180 Gallon Standard
350 Liter (120cm Deep)
Show 1 more tank size
Redear Sunfish Feeding & Diet Considerations
The Redear Sunfish is a predatory species that will readily consume small fish, so nano or bite-sized tankmates should be avoided, will hunt and eat ornamental shrimp, making it unsuitable for shrimp-focused setups, and actively feeds on snails and can be used as a natural snail population control.
Frequently Asked Questions About Redear Sunfish
How big does Redear Sunfish get?
Redear Sunfish (Lepomis microlophus) typically reaches a maximum adult size of approximately 25 cm. They have a compressed body shape and a moderate growth rate.
What tank size does Redear Sunfish need?
A minimum aquarium volume of 280 litres and a tank length of at least 120 cm are recommended for Redear Sunfish. This ensures enough swimming space and helps maintain stable water conditions.
What water parameters does Redear Sunfish need?
Redear Sunfish thrives in freshwater only conditions with a temperature range of 10–26°C, a pH between 6.5 and 8.5, and a general hardness of 8–20 dGH. A low water flow is preferred.
Is Redear Sunfish peaceful or aggressive?
Redear Sunfish is classified as semi-aggressive with an aggression score of 6 out of 10. They can work in community setups but may clash with certain tankmates.
Can Redear Sunfish live alone?
Yes, Redear Sunfish can be kept singly or in a group. They are flexible and adapt well to both setups.
Is Redear Sunfish safe with shrimp?
No. Redear Sunfish is known to eat ornamental shrimp and is not recommended for shrimp tanks. Even larger shrimp species like Amano Shrimp may be at risk.
Will Redear Sunfish eat snails?
Yes. Redear Sunfish actively feeds on snails. While this can be useful for controlling pest snail populations, it means decorative snails should not be housed with this species.
Does Redear Sunfish have any special tank requirements?
Yes. Redear Sunfish benefits from sand (sifters) and shells (breeding/hiding) in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.
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 Redear Sunfish
These plants pair well with Redear Sunfish based on shared water preferences, layout fit, and how likely they are to hold up in the same aquarium.
Amazon Frogbit
Limnobium laevigatum
Asian Watergrass
Hygroryza aristata
Asian Watermoss
Salvinia cucullata
Carolina Mosquito Fern
Azolla caroliniana
Common Duckweed
Lemna minor
Crystalwort
Riccia fluitans
Fish Similar to Redear Sunfish
Longear Sunfish
Lepomis megalotis
A strikingly beautiful North American native fish often likened to a cold-water cichlid. Known for their brilliant blue and orange coloration and elongated opercular flaps ('ears'). They are highly territorial, predatory, and require a large, unheated or cool-water aquarium with plenty of structure.
Redbreast Sunfish
Lepomis auritus
A colorful, North American native freshwater fish known for its bright orange-red belly and an elongated, solid black opercular flap ('ear'). As a temperate species, they thrive in unheated aquariums. They are aggressive, territorial predators that will dig nests in the substrate and consume any tank mate small enough to fit in their mouths.
Pumpkinseed
Lepomis gibbosus
A beautiful but aggressive North American native sunfish. Known for its vivid orange, blue, and green speckling and the distinctive red spot on its gill cover. As a temperate/coldwater species, it does not require a heater. They are highly territorial, intelligent, and have large appetites, functioning much like Central American Cichlids in the aquarium.
Bluegill Sunfish
Lepomis macrochirus
A highly active and intelligent North American native fish. Known for their deep, laterally compressed bodies and the distinctive dark spot at the base of the dorsal fin. They are predatory and territorial, often treated as 'coldwater cichlids' by hobbyists. Because they grow large and are highly active, they require significant swimming space and heavy filtration.
Green Sunfish
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A robust, highly adaptable, and extremely aggressive North American native fish. Known for its vivid blue-green iridescent facial lines and yellow-margined fins. Due to its large mouth, heavy build, and extreme territoriality, it is often considered the 'Oscar of native fish' and should be kept singly or with large, robust tank mates in spacious setups.
Orangespotted Sunfish
Lepomis humilis
The Orangespotted Sunfish is one of the smallest and most colorful North American sunfishes, making it an excellent choice for unheated or temperate aquariums. They are hardy, highly interactive, and possess big personalities. Like most centrarchids, they are territorial micropredators that will hunt small invertebrates. Males dig nests in the substrate during breeding season.