As seen in Shimmy, Shimmy, Pow; Field & Stream article dating back to November 2013, and replicated by many, here is where to find the ones that swim properly.
5 inches, 3 articulated sections.
WARNING: Cancer & Reproductive Harm -
This product may contain chemicals known to the state of California to cause cancer, birth defects or other reproductive harm.
http://p65warnings.ca.gov/
