I find it curious how he calls the girls "young sweetfishes". At first I though it may be a reference to 小女子 (kounago), which means both "young lancefish" and "little girl", but that's not sweetfish (it would be "chiayu", 稚鮎, or "wakaayu", 若鮎, perhaps even "hiuo", 氷魚). Since they are not remotely similar (no more than with another unrelated fish), that was most likely just my misunderstanding.
Still, what a weird lingo the ex-superintendent is using here.