A niche is defined as the role that an organism plays in its environment. It includes how the species meets its needs such as food and shelter. A niche also includes how a species survives, reproduces, and the species' interactions with the biotic (living) and abiotic (nonliving) features of its environment.
The lionsfish is a popular aquarium fish. It is maroon in color with white stripes. Lionsfish are found in coral reefs of the South Pacific and Indian Oceans at depths from 1-1000 feet along hard bottoms. They have sharp spines that are poisonous to organisms that are penetrated by them. They also use their wide pectoral fins to corner their prey. These defenses enable the lionsfish to be predators to many smaller fish, shrimp, and crab. As tertiary consumers on the top of a coral reef's food web, lionsfish have the potential to cause havoc on such communities.
When introduced to new communities, lionsfish have the potential to become an invasive species and out rule other predators. The prey in such communities are not savvy in how to defend themselves from the lionfish's hunting strategies. In such a situation, the lionsfish has the ability to take over the niche of the native species in their ecosystems.