Those of you who caught Friday night’s return of Shark Tank saw one of the show’s best episodes — compelling high-stakes, drama-filled negotiations featuring a confident Mark Cuban as guest star. Too bad so few watched it: Tank returned to 4.8 million viewers and a 1.2 preliminary adults 18-49 rating, coming in fourth place at 8 p.m., as well as being down considerably from last year’s Sunday night premiere. The show was actually edged out by (really, America?) Steve Buscemi guest starring on NBC’s Who Do You Think You Are (6.6 million, 1.3). Over on Fox, Fringe (3.9 million, 1.5) fans rewarded the show following its fourth season pickup, rising 15 percent from last week’s low.