From The Collaborative International Dictionary of English v.0.48 [gcide]: Rudd \Rudd\, n. [See Rud, n.] (Zool.) A fresh-water European fish of the Carp family ({Leuciscus erythrophthalmus}). It is about the size and shape of the roach, but it has the dorsal fin farther back, a stouter body, and red irises. Called also redeye, roud, finscale, and shallow. A blue variety is called azurine, or blue roach. [1913 Webster]
From The Collaborative International Dictionary of English v.0.48 [gcide]: Azurine \Az"u*rine\, a. [Cf. Azurn.] Azure. [1913 Webster] From The Collaborative International Dictionary of English v.0.48 [gcide]: Azurine \Az"u*rine\, n. (Zool.) The blue roach of Europe ({Leuciscus c[ae]ruleus}); -- so called from its color. [1913 Webster]