The yellow encrusting sponge (Biemna anisotoxa) is a species of sea sponge in the family Biemnidae.

[1] This sponge is known from the west coast of South Africa to Port Elizabeth.

[2] The yellow encrusting sponge is beige-yellow and grows in crusts of up to 1 cm thick.

It has small but distinct oscula which may be slightly raised from the surface of the sponge.

[2] This sponge lives on rocky reefs and other hard surfaces from 10-12m.