Sepioteuthis lessoniana, commonly known as the bigfin reef squid, is notable for its rapid color-changing ability, used for communication and camouflage. Found in warm coastal waters, it displays fascinating social behaviors and is an important predator and prey in its marine ecosystem.

Sepioteuthis lessoniana, commonly known as the Bigfin Reef Squid, is primarily found in the Indo-Pacific region. This includes areas such as the Red Sea, the Indian Ocean, and the western Pacific Ocean. Countries where it is commonly observed include Japan, Australia, the Philippines, and parts of Southeast Asia.

Sepioteuthis lessoniana typically inhabits warm, coastal waters. It is often found in shallow areas near reefs, seagrass beds, and mangroves. The species prefers water temperatures ranging from 20°C to 30°C and can often be seen in water depths ranging from the surface to about 100 meters.

The Bigfin Reef Squid occupies a niche as both a predator and prey within its ecosystem. It feeds on small fish, crustaceans, and other invertebrates, using its speed and agility to capture prey. In turn, it is preyed upon by larger fish, marine mammals, and birds. The species plays a crucial role in the marine food web and is known for its dynamic camouflage abilities, which help it evade predators and communicate with other squids.