Cleithracara maronii, commonly known as the Keyhole Cichlid, is a small freshwater fish native to slow-moving rivers and streams in South America. It displays a distinctive keyhole-shaped black spot on its side. Known for its peaceful temperament, it thrives in densely planted aquariums.

Cleithracara maronii, commonly known as the Keyhole Cichlid, is native to the northern part of South America. It is primarily found in the countries of Venezuela, Guyana, Suriname, and French Guiana. The species is prevalent in the coastal river basins and drainages of these regions.

The Keyhole Cichlid inhabits freshwater environments, typically preferring slow-moving or still waters such as those found in rivers, streams, and flooded forest areas. The water in these habitats is generally soft and slightly acidic, with temperatures ranging from 24°C to 28°C (75°F to 82°F). The regions they inhabit often have dense vegetation and submerged wood, providing ample cover and breeding sites.

Cleithracara maronii occupies a niche as a benthopelagic species, meaning it is typically found near the bottom of its aquatic environment, but it can also inhabit midwater areas. It feeds on a diet of small invertebrates, detritus, and plant material, contributing to the ecosystem by helping to control insect populations and recycling organic matter. The species is known for its adaptability to different microhabitats within its native range, which allows it to thrive in diverse environmental conditions.