My great uncle used to make his own Wonder Wobbler ripoff, using the business end of a teaspoon with all but 2cm of handle cut off. Drill a hole in each end for split rings, then a swivel on the front and a treble on the back. Then depending on the spoon, usually a bit of panel beating with a ball-peen hammer to get it swimming right. Every birthday/xmas I'd get a couple and they were dynamite. As he had it, the realistic elements (tail, scales, eyes etc) didn't do anything - they were just there for the humans - it was all about the shiny metal and the action.
I should get off my bum and make some myself one day - I've only got one rusty one left.