Like other brittle stars, Ophionereis reticulata has a small flattened, pentagonal disc and five narrow, elongated arms.

The aboral (upper) surface of the disc is covered with small plates and is pale grey with a network of fine reddish-brown lines, giving it its common name.

[4] Ophionereis reticulata is an herbivore and filter feeder, but detritus and fragments of polychaete worm have also been found in its stomach.

[5] It mainly consumes red and green algae and diatoms which it catches by raising one or more of its arms into the passing water current while keeping its disc concealed.

If an arm is attacked by a predator it can easily break off in a process known as autotomy, and the brittle star can later regenerate a new limb.