Yes "Down in a Diving Bell" should work fine.

Maybe you could work up something from one of my mother's children's books entitle DEEP SEA FARM (search for Dahlov Ipcar on Bookfinder.com). She had all kinds of faniful scenes and puns about the farm animals, the sea cows and sea horses, hunting for the sea wolf. harvesting the sea cucumbers, neat stuff like that. You'd enjoy the book anyway; they're generally available in good used condition on the internet but most haven't been reprinted in years.

You probably don't want "The Old She-Crab."

Cheerily,
Charley Noble