Sometimes the cushions are plate-like, cup or fan-shaped, and older individuals may have protuberances and appear lumpy or shaggy.

The colour of this sponge is yellowish, beige or light brown, the texture is soft, and the tissues fragile and crumbly.

[2][3] It may be confused with Dysidea fragilis, but that species is whiter and lacks the megascleres and microscleres present in Biemna variantia.

It grows on vertical rock faces where there is moderate water movement, under boulders and on stones, gravel and mud, at depths varying from the intertidal zone to 1,600 m (5,200 ft).

After fertilisation, the embryos are brooded inside the sponge, and when they reach the last embryonic stage, they pass out through the oscula into the water column.