The Collaborative International Dictionary of English v.0.48:

Ichthyophthira \Ich`thy*oph*thi"ra\, n. pl. [NL., fr. Gr.
   'ichqy`s, -y`os, a fish + ? a louse.] (Zool.)
   A division of copepod crustaceans, including numerous species
   parasitic on fishes.
   [1913 Webster]