Growth form Vethaak et al. (1982) described six distinct forms (as well as intermediate forms) including apparently free-living forms, low incrusting forms and massive forms with elaborate chimneys (see Vethaak et al., 1982 for further details and photographs).
A life span of about 3 years was suggested in Fish & Fish (1996). Unlike Halichondria bowerbanki, Halichondria panicea survive the winter in a normal, active state in the Oosterschelde (Vethaak et al., 1982).