I see now. He has to move back home if his grades drop, so his family dispatches their most distracting maid. As expected, you do not become so wealthy without this kind of ruthless cunning.
Another name for fish of the genus Sillago. They often live in coastal water and are quite abundant, so they're commonly caught by Japanese fishing vessels. The Japanese word is 鱚 (キス - kisu), which sounds just like their pronunciation of the English word "kiss", hence the wordplay.