Amphimedon compressa, the erect rope sponge, red tree sponge, red tubular sponge, or red sponge is a demosponge found in southern Florida, the Caribbean Sea, and the Bahamas. It can be deep red, orange, brown, or black.

Taxonomy The erect rope sponge used to be classified as Haliclona rubens, but this was determined to be a synonym of Haliclona compressa. This name, however, is no longer accepted, and the World Porifera Database lists this species as Amphimedon compressa – Duchassaing & Michelotti, 1864.

Description Amphimedon compressa can grow to a length of 40 cm (16 in) and a diameter of 4 cm (1.6 in), but it is usually smaller in shallow water. The tree-like curved branches grow from a basal encrusting mass, but very occasionally this sponge grows as a small, unbranched, flattened hemisphere. Many small osculi are found on the branches. It is usually a dull dark red, but the colour varies and it is sometimes black, dark brown, greyish-brown, bright red, or orange. In dark positions under overhangs, it grows in mats and its colour is weak.

Distribution The erect rope sponge grows as part of the coral reef community.