Giant, man-eating fish are usually the province of the SyFy channel’s Saturday-night movie franchise. It seems like every other film there involves some giant, mutant bloodthirsty creature on the rampage. But tonight, The National Geographic Channel introduces “Fish Warrior: Catfish Attack” (7 p.m., National Geographic).

Adventure angler and conservationist Jakub Vagner goes in search of legendary catfish, some rumored to weigh as much as half a ton and feed on small animals, even people. Yikes! He doesn’t find a fish that large but does come face-to-mustached-face with the wels catfish in France, a 6-foot monster that leaves him with a rather nasty bite mark. “Fish Warrior” proves to be a perfect lead-in for the new series “Beast Hunter” (8 p.m., National Geographic) another “documentary” show the blends and confuses the realms of science, fiction and fantasy.

• A rather cruel slang term used to refer to the state of Florida as “God’s waiting room,” owing to the number of elderly retirees spending their golden years in the sun. When I think of the place TV shows go to retire and (possibly) expire, I think of Friday nights.

Folks who sift the ratings tea leaves feel “The Defenders” is all but certain to follow “Medium” to the cancellation bone pile and consider “Blue Bloods” a bit of a tossup. “Fringe” is also on the fence as we enter the last few months of the season. Friday nights have long been a place where Fox series drift away. Remember “The Good Guys”? Many hold out hope that “Fringe” and its faithful cult audience will prevail. I seem to remember much the same thing being said about “Dollhouse,” a Friday night failure that not even producer/creator Joss Whedon’s many fans could save.

• A full decade before her Best Actress Oscar for “The Black Swan,” Natalie Portman portrayed a pregnant 17-year-old abandoned by her boyfriend in a Wal-Mart parking lot in the 2000 melodrama “Where the Heart Is” (7 p.m., WE). At the time, most viewers knew her from her difficult role of spouting wooden dialogue in George Lucas’s dreadful “Star Wars” prequel, “The Phantom Menace.”

• The 2009 Iraq war drama “The Hurt Locker” (7 p.m., The Movie Channel) took the “ticking-time bomb” motif all the way to the Best Picture Oscar.

Tonight’s other highlights

• The defense of a couple accused of killing a yoga instructor stretches Nick and Pete’s partnership in new directions on “The Defenders” (7 p.m., CBS).

• Kim Cattrall looks at her family tree on “Who Do You Think You Are?” (7 p.m., NBC).

• Bill Murray stars as a counselor in the 1979 summer camp comedy “Meatballs” (7 p.m., IFC).

• A raucous loser (Jack Black) shakes up a prep school in the 2003 comedy “School of Rock” (7 p.m., TBS).

• An elite prep school becomes a crime scene on “CSI: NY” (8 p.m., CBS).

• Thieves tamper with gravity itself on “Fringe” (8 p.m., Fox).