... a harpoon?! But I don't want to hurt Fishy. Hotarumaru would be upset if he came back and found his pet was hurt.

[ It's true. Hotarumaru was the one who initially brought the alien fish to Swordhaus, but he disappeared a short time after. This left Kogitsunemaru to pick up the slack and carry on the torch! ]

A blanket would be wise. Perhaps if I cover its eyes, it will think it is night and will fall asleep.

[ He smiles cheerily, though it fades as he hums with a thought. ]

Do fish sleep, Koumei?