There were two variants of this kit, but since I never look in the box, I keep forgetting which one I have. I picked it up in a tiny shop in Seattle’s Chinatown (ahem, International) district back in 2001 and haven’t had a chance to open it since.
It really swims, though I’ve never had the courage to test it myself. The tanks have a piece of styrofoam in them to make them float (see pic #4). Known as RMZ-05 Aquadon (OJR), or Aquazoid (OER), or “frog looking thing” here.