Keyhole Cichlid

Cleithracara maronii

Cichlids - South American

A remarkably peaceful and shy South American cichlid, named for the distinctive keyhole-shaped black marking on its flank. Unlike many of its cousins, it rarely digs or destroys plants and makes an excellent resident for a peaceful community tank. When stressed or frightened, it can rapidly mottle its colors to blend in with its surroundings.

At a Glance

Adult Size10 cm
Body ShapeCompressed
Growth RateModerate
TemperamentPeaceful
Water TypeFreshwater Only
Flow PreferenceLow
Waste OutputMedium
StockingSolo or group

Tank Requirements

Minimum Volume110 L
Minimum Length80 cm
FlowLow
Water TypeFreshwater Only
Must-Haves in the Tank
Driftwood (Digestion/Hiding)Plants - Densely coveredLeaf Litter/Blackwater

Find the right tank equipment

Browse tanks, décor, and equipment suited for this setup.

Water Parameters

Temperature2228°C
pH67.5
Hardness215 dGH

Shop water care essentials

Keep water parameters stable with the right testing and heating gear.

Temperament & Compatibility

Aggression LevelPeaceful
2/10
Where They Swim
Surface
Mid-level
Bottom
Stocking Guidelines
Keep at Least1 (solo is fine)
Max per TankNo limit
Can Live Alone?Yes
Behavior Traits
Shy / Slow Moving (Easily Stressed)Fry Predator

Available Varieties

Each variety inherits the species defaults above. Only differences are highlighted.

Standard

Same care requirements as the base species

Also known as: Adult, Unsexed

Keyhole Cichlid Care Guide Summary

The Keyhole Cichlid, scientifically known as Cleithracara maronii, belongs to the Cichlids - South American family group. Adults reach a maximum size of approximately 10 cm and have a compressed body shape with a moderate growth rate. Classified as peaceful, this species primarily occupies the mid-level and bottom zones of the aquarium and produces a medium level of biological waste.

To thrive, the Keyhole Cichlid requires a freshwater only aquarium with a minimum volume of 110 litres and a tank length of at least 80 cm. Water temperature should be maintained between 22°C and 28°C, with a pH range of 67.5 and a general hardness of 215 dGH. A low water flow is preferred. An aquarium test kit can help you monitor these values.

Due to its specialist needs, the Keyhole Cichlid is best suited for fishkeepers who can provide a carefully planned setup. The Keyhole Cichlid is typically available in one standard form.

Keyhole Cichlid Habitat Setup

When setting up an aquarium for the Keyhole Cichlid, 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 driftwood, which can serve as both a hiding place and a dietary supplement, leaf litter or blackwater tannins to replicate their natural soft-water habitat, and dense planting to provide cover, break sightlines, and reduce stress.

Keyhole Cichlid Compatibility Notes

Classified as peaceful, the Keyhole Cichlid is adaptable and can be kept singly or in a small group, offering flexibility when planning a community tank. When choosing tankmates, boisterous or fast-moving tankmates may cause this species undue stress. Selecting tankmates that favour different water layers from the mid-level and bottom zones can help reduce competition and territorial overlap.

Frequently Asked Questions About Keyhole Cichlid

How big does Keyhole Cichlid get?+
Keyhole Cichlid (Cleithracara maronii) typically reaches a maximum adult size of approximately 10 cm. They have a compressed body shape and a moderate growth rate.
What tank size does Keyhole Cichlid need?+
A minimum aquarium volume of 110 litres and a tank length of at least 80 cm are recommended for Keyhole Cichlid. This ensures enough swimming space and helps maintain stable water conditions.
What water parameters does Keyhole Cichlid need?+
Keyhole Cichlid thrives in freshwater only conditions with a temperature range of 22–28°C, a pH between 6 and 7.5, and a general hardness of 2–15 dGH. A low water flow is preferred.
Is Keyhole Cichlid peaceful or aggressive?+
Keyhole Cichlid is classified as peaceful with an aggression score of 2 out of 10. They are generally well-suited to peaceful community tanks.
Can Keyhole Cichlid live alone?+
Yes, Keyhole Cichlid can be kept singly or in a group. They are flexible and adapt well to both setups.
Does Keyhole Cichlid have any special tank requirements?+
Yes. Keyhole Cichlid benefits from driftwood (digestion/hiding), plants - densely covered, and leaf litter/blackwater in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.

Similar Species

Convict Cichlid

Amatitlania nigrofasciata

Cichlids - Central American
15 cm Aggressive

One of the most ubiquitous and hardy cichlids in the hobby. Named for their black-and-white prison stripe pattern, Convicts are infamous for their intense aggression, especially when breeding (which they do readily). They are intelligent, wet pets that rearrange their tank décor constantly. Best kept in species-only tanks or with other robust Central American cichlids.

Kribensis

Pelvicachromis pulcher

Cichlids - African
10 cm Semi-Aggressive

A vibrant and highly popular dwarf cichlid native to the slow-moving rivers of West Africa. Unlike Rift Lake African cichlids, they prefer soft, slightly acidic water and densely planted tanks. They are generally peaceful in a community tank but become fiercely territorial and aggressive when breeding, often digging pits in the substrate and claiming the bottom zone. They are cave spawners and require hiding spots like driftwood or coconut shells.

Texas Cichlid

Herichthys cyanoguttatus

Cichlids - Central American
30 cm Aggressive

The Texas Cichlid is the only cichlid species native to the United States. Known for their striking pearlescent blue/green spots and extreme territorial behavior, they require large tanks and robust filtration. They are notorious for rearranging aquariums, digging massive pits, and destroying live plants.

Firemouth Cichlid

Thorichthys meeki

Cichlids - Central American
15 cm Semi-Aggressive

A popular Central American cichlid famous for the bright red coloration on its throat and belly, which it flares to intimidate rivals. They are earth-eaters, constantly sifting sand for food. While territorial, especially during breeding, they are relatively peaceful for a cichlid of their size compared to larger Central American counterparts.

Freshwater Angelfish

Pterophyllum scalare

Cichlids - South American
15 cm Semi-Aggressive

The most iconic South American Cichlid, known for its distinct arrowhead shape and majestic fins. While domestic strains are hardy, they remain cichlids: they are semi-aggressive predators that will eat any fish small enough to fit in their mouths (like Neon Tetras). They form loose shoals as juveniles but pair off and become territorial as they mature. Height is more important than length for this species.

Green Terror

Andinoacara rivulatus

Cichlids - South American
25 cm Aggressive

A large, incredibly colorful, and highly aggressive South American cichlid. Known for their striking metallic green/blue scales and vibrant orange or white tail margins. As their name suggests, they are highly territorial and require very careful tankmate selection, usually only coexisting with other large, robust cichlids or armored catfish in very large tanks.