Dictyoceratid sponges do not have the usual mineral spicules (rod-like structures that make up many sponge skeletons). Instead they are made entirely of elastic spongin (protein) fibers organized into networks. This makes their bodies tough and flexible. They are easy to squish, but hard to tear. The surface of their body is typically raised up in little cone-shaped points, making it look like they have goosebumps. The bumps are actually projections from the underlying skeletal fibers, and in some species the bumps are expanded into an armor-like covering. Dictyoceratids have the habit of incorporating debris (such as sand grains or spicules shed by other sponges) into their skeletons, making them harder.

With the exception of one group of carnivorous sponges, all sponges are filter-feeders. The design of their bodies is mostly about filtering food, and does not include a mouth or stomach. A sponge body is basically a tube or sack with lots of small pores (ostia) for water to come in and other, larger pores (oscula) for water to get out. What happens in between varies. In the simplest sponge bodies, the water enters the ostia pores and then dumps into a large, central area called the atrium. The most complex sponge bodies have a whole system of canals leading to smaller chambers where water gets filtered. In any case, the filtering is done by little hair-like flagella that trap bacteria and tiny ocean organisms (plankton) before the water gets expelled from the sponge. Sponge wastewater may be flushed out forcefully enough to travel 10 feet.