Tropical Fish Shop is a "match 3" game a lot like Bejeweled, but with underwater theme. You have to periodically match "air bubbles" to increase your air supply, and you have requirements to do X number of certain creature per "trip".
There's a story about how Annabel, who wants to live near a beach and do diving all the time, need to do this for a dive shop (who also sells tropical fish).
Not bad.
7 out of 10
http://www.appbrain.com/app/tropical-fish-shop/com.sgg.annabel