Vic Gorelick (colors), Ray Bailey (artist), D.J. Arneson (writer)
From Undersea Agent #2 - 10 pages - Bored and foolish, Skooby goes for an underwater dive and gets chased by a giant grouper. Things get worse and it falls on Renata and Davey Jones to find him and for Jones to use his new powers to save him.
Here are the pages I have of it.