I looked for these frogs South of the docks as recommended. The frogs seemed to be somewhat rare. Not many along the shore, I had better luck finding them in the water. The sea turtles might be place holders they share the same area along shore and in the water so I killed them too.
I visited Nedaria's with my 22 ranger yesterday (12/30/03) and many of the frogs conned dark blue to me. The con range was dark blue, white, yellow. I didn't see any red frogs. So I suspect the level range for the cove frogs is closer to 20-25.
I killed many frogs and looted four eyes. I could not find the iksar for the frog eye quest. In the dozen or so frogs I killed, there were four eyes and one skin.