Cavalcade where he was the lead, but for the Silver and Bronze Age, he was always part of a team, either with the JSA or working with Barry Allen's Flash....except for one special story by Robert Kanigher and Murphy Anderson in Flash #201 (November, 1970).
Let's take a quick look at it!
Finale For A Fiddler!
Shame Jay's old foe, the Fiddler has his sights set on causing trouble there, but, even though he isn't as fast as he used to be, Flash stops the Fiddler!
JLA #91, Joan next in Flash #215, Fiddler next in All-Star Comics #63 with the ISW, and Turtle Man doesn't appear again until after the Crisis On Infinite Earths, where he teams up with Barry's version of the Turtle to face Wally West as the Flash!