It is found in shallow temperate and warm waters in the western Atlantic Ocean and the Caribbean Sea and has spread worldwide as a fouling organism.

Colonies of Amathia verticillata resemble miniature trees up to a metre (yard) wide and consist of a dense mass of feeding zooids known as autozooids connected to each other by slender branching stolons 0.5 mm (0.02 in) in diameter.

[2][3] Colonies of Amathia verticillata are found in shallow water in the tropical and subtropical western Atlantic and the Caribbean Sea and many other parts of the world.

Amathia verticillata is a fouling organism and its typical habitat is growing on the blades of seagrasses, the thallus of large seaweeds, the roots of mangroves, rocky reefs, the shells of bivalve molluscs, piers, breakwaters and other man-made structures, the hulls of boats, floating masses of seaweed and other floating debris.

It can develop into huge aggregations and cause fouling of fishing gear, block sea-water inlets, out-compete native species and upset food chains by filtering phytoplankton from the water.