[3] It is rare in the southern part of its range, but in the Pacific Northwest, can be quite common in boulder/cobble habitats with large populations of its sponge prey, Halisarca sp.

Most records of Hallaxa chani are from the intertidal zone, but Millen (1983 and 1989) found it subtidally at unspecified depths in British Columbia and Alaska.

[3] Hallaxa chani preys exclusively on Halisarca sp., a slick-textured dendroceratid sponge lacking both spicules and spongin fibers (Goddard, 1981, 1984, 1998).

As noted by Nybakken & McDonald (1981), nudibranchs that specialize on ascidians or fleshy ctenostome bryozoans have a radula dominated by large, paired, wing-shaped lateral teeth.

Dorids specializing on dendroceratid and dictyoceratid sponges have thin, comb-like outer lateral teeth with multiple denticles (Goddard, 1981, personal observations; Rudman, 1984; and see electron micrographs of radulae in Gosliner & Johnson, 1994).