The size depends on the frog you decide on, though a good rule of thumb is 10 gallons per frog. Leucs are common and do well in groups. And the linkto the video didn't work, but I'm pretty sure the frogs you described are a D. Tinctorius morph, such as cobalt, or blue jeans. My cat doesn't bother my frogs, though it depends on the kitty. Most tanks can be on a dresser or table without issue, unless it's HUGE.