Cairns Aquarium is a public aquarium in central Cairns, Queensland, designed around the freshwater and marine environments of tropical North Queensland. Its exhibits represent habitats ranging from rainforest streams and wetlands to mangroves, rivers, and the Great Barrier Reef. The aquarium holds thousands of animals and provides a way to see species from ecosystems that extend across the region without leaving the city. Large underwater viewing areas allow visitors to observe sharks, rays, reef fish, and other marine animals, while freshwater exhibits highlight the connection between inland waterways and the coastal environment.

The aquarium places particular emphasis on the relationship between North Queensland's ecosystems. Exhibits trace water from mountain rainforests through rivers and wetlands before reaching mangrove forests, coastal waters, and the Great Barrier Reef. This approach reflects the ecological connections between habitats rather than treating each environment as separate. Interpretive displays provide information about local wildlife and conservation, while presentations and keeper talks introduce visitors to individual species. The aquarium also has a strong focus on education, with programs designed to explain the region's biodiversity and the importance of protecting its waterways and marine environments.

Several major exhibits provide close views of tropical Australian wildlife. The Great Barrier Reef galleries contain corals, reef fish, turtles, and other marine species, while the Oceanarium includes a large underwater tunnel and viewing areas for larger animals such as sharks and rays. The aquarium's freshwater environments feature species from North Queensland's rivers and wetlands, and the Cairns Turtle Rehabilitation Centre provides care for injured or sick marine turtles. Rainforest and mangrove exhibits introduce animals adapted to these distinctive habitats, allowing visitors to see how closely Cairns' coastal ecosystems are connected to the surrounding tropical landscape.

The aquarium also provides insight into some of the less familiar animals of tropical Queensland, including freshwater fish, reptiles, amphibians, and invertebrates. Its exhibits feature species associated with the Wet Tropics and Great Barrier Reef, two internationally recognized natural areas surrounding Cairns. Food is not a central part of the attraction, although the aquarium's on-site restaurant uses the setting of its marine exhibits as part of the dining experience. As an indoor attraction focused on local ecosystems, Cairns Aquarium offers an accessible introduction to the region's wildlife before visitors explore the rainforest, coastline, and reef environments beyond the city.