Keyhole Cichlid
Cleithracara maronii
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.
Keyhole Cichlid At a Glance
Keyhole Cichlid Tank Requirements
Will Keyhole Cichlid fit in your tank?
Care guides tell you what Keyhole Cichlid needs, the next question is whether your tank can safely provide it. Test Keyhole Cichlid against your tank size, maintenance needs, and the fish you already keep before you buy.
Keyhole Cichlid Water Parameters
Keyhole Cichlid Temperament & Compatibility
Keyhole Cichlid 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 6–7.5 and a general hardness of 2–15 dGH. A low water flow is preferred.
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.
Who Keyhole Cichlid Is Actually For
Keyhole Cichlid 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 driftwood.
The most common mistake is buying Keyhole Cichlid 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.
Keyhole Cichlid Recommended Tank Sizes
Standard aquarium sizes that meet the minimum volume and length requirements for Keyhole Cichlid.
30 Gallon Breeder
40 Gallon Breeder
55 Gallon Standard
60 Gallon Breeder
75 Gallon Standard
90 Gallon Standard
Show 12 more tank sizes
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.
Useful setup supplies
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Guidarium Editorial Desk
Reviewed against Guidarium care, stocking, and compatibility standards. Read the editorial policy.
- Last reviewed
- April 28, 2026
- Last updated
- April 28, 2026
- Issues or corrections?
- Contact the editorial team
Top Tank Mates for Keyhole Cichlid
These fish are strong compatibility matches for Keyhole Cichlid based on water preferences, temperament, adult size, and tank behavior.
Marbled Hatchetfish
Carnegiella strigata
Ideal Tank MatesClown Killifish
Epiplatys annulatus
Ideal Tank MatesTrapdoor Snail
Cipangopaludina chinensis
Ideal Tank MatesTiger Pleco (L002)
Panaqolus sp. L002
Ideal Tank MatesTandanus Catfish
Tandanus tandanus
Ideal Tank MatesStarlight Bristlenose Pleco (L183)
Ancistrus dolichopterus
Ideal Tank MatesPlants That Suit Keyhole Cichlid
These plants pair well with Keyhole Cichlid 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
Beckett's Water Trumpet
Cryptocoryne beckettii
Broad-leaved Crypt
Cryptocoryne pontederiifolia
Carolina Fanwort
Cabomba caroliniana
Fish Similar to Keyhole Cichlid
Checkerboard Cichlid
Dicrossus filamentosus
A striking, slender South American dwarf cichlid known for its distinct black checkerboard pattern along its flanks. Unlike many cichlids, they are exceptionally peaceful community fish. They are strict blackwater species, requiring very soft, acidic water, sand substrate, and leaf litter to thrive.
Rainbow Cichlid
Herotilapia multispinosa
Widely regarded as one of the most peaceful and beginner-friendly Central American cichlids. They are known for their vibrant gold, orange, and black coloration which intensifies during breeding. In the wild, they inhabit muddy, slow-moving waters and have specialized teeth for grazing on algae. While peaceful for a cichlid, they become aggressively territorial when spawning and their herbivorous diet means they will happily consume soft-leaved aquarium plants.
Sajica Cichlid (T-Bar Cichlid)
Amatitlania sajica
A relatively manageable Central American cichlid closely related to the Convict Cichlid. It earns its 'T-Bar' name from a prominent dark vertical bar crossed with a horizontal stripe on its flank. While more peaceful than many CA cichlids, they are dedicated parents and become fiercely territorial when breeding, often excavating large pits in the substrate. They thrive in moderately hard water.
Black Acara
Cichlasoma bimaculatum
A hardy, adaptable, and robust South American cichlid. They are relatively peaceful compared to larger cichlids but become highly territorial when breeding. Known for their oval-shaped body, greyish-green coloration, and a distinct black mid-lateral spot. They naturally sift through the substrate and require sandy bottoms.
Threadfin Acara
Acarichthys heckelii
A stunning, generally peaceful South American cichlid closely related to the 'Earth-eaters' (Geophagus). They are famous for the long, trailing red filaments extending from their dorsal fins. They continuously sift substrate for food, making fine sand an absolute requirement for their gills and natural behaviors. While relatively peaceful in a community of similarly sized fish, they become fiercely territorial during breeding.
Black Belt Cichlid
Vieja maculicauda
A large, powerful, and strikingly colored Central American cichlid known for the distinctive vertical black band across its midsection and vivid red flushing on its throat and tail. They are highly territorial, aggressive, and notorious for re-arranging the aquarium. They are primarily herbivorous in the wild but will eat almost anything, including smaller fish. They cannot be kept in planted tanks.