Δελφῖνα νήχεσθαι διδάσκεις: ἐπὶ τῶν ἐν ἐκείνοις τινὰ παιδοτριβούντων, ἐν οἷς ἤσκηται → Teaching dolphins to swim: is applied to those who are teaching something among people who are already well versed in it
ἰχθυαῑος, -α, -ον (Μ)
όμοιος με ψάρι.
[ΕΤΥΜΟΛ. < ἰχθύς + επίθημα -αιος (πρβλ. πηχυ-αίος)].