If swim you must (moi) then you must swim with fins. They build speed and work those kickers like crazy... which translates to tighter kickers... which we all can appreciate in fishnets.
Tilos Getaway Snorkel/Lap Fins Compact for taking to the pool, and also for taking on snorkel trips. Open heal design, can also fit a dive boot!!! $25.97 from www.kirkscubagear.com