Spine-cheeked anemonefish surrounded by bubble-tip anemone, Milne Bay, Papua New Guinea

In the bubble-tip zone. Spine-cheeked anemonefish

That bright fish hiding in the anemone? That's the spine-cheeked anemonefish, or the maroon clownfish, and it is not just a cute creature. Native to the Indo-Pacific, from western Indonesia to Taiwan and the Great Barrier Reef, this species lives on the edges of coral reefs. This fish is easily distinguished by the spine extending from each cheek—hence the name. Groups of spine-cheeked anemonefish form around a single dominant female, and if she disappears, the top male steps up—literally changing sex to take her place. It thrives in warm, shallow waters and sticks close to its chosen sea anemone. The closest marine companion of a spine-cheeked anemonefish is the bubble-tip anemone, as seen in the image. These anemones don't all look alike—their appearances often vary with age, depth and whether they host anemonefish. This species offers the perfect mix of cover and protection.

India's aquatic ecosystems are also rich with an incredible variety of fish species, spanning freshwater, brackish and marine environments—from the rivers of Bengal to the coasts of the Arabian Sea and the Indian Ocean. The country is home to around 940 freshwater species, making up about 38% of its total fish diversity. Remarkably, nearly 500 of these are endemic, found nowhere else in the world.