Have no doings with the Erythynus. This is the thirty-third
Symbol of the Protreptics of Iamblichus. The Erythynus is a fish
called by Pliny (ix. 77) erythrinus, a red fish with a white
belly. Pythagoras used this fish as a symbol of a braggadocio,
which has a lily liver. Have no doings with those who are
tongue-doughty, but have white stomachs (where stomach means
true courage). Source: Dictionary of Phrase and Fable, E. Cobham
Brewer, 1894