I saw this a few months back, and all around, I was disappointed. Some of the side stories were interesting, especially the one about the worm fish (?) that lives underground in leaf litter from one rainy season to the next. But all around, I didn't think much of it. Most of the underwater filming was so dark and murky that it was hardly worth watching. And the main premise of the show was to see if anything new and weird was living in the deepest parts of the river. Well, when they finally got down there, they discovered... a fish already known to science! Shocking! Amazing! Boring! And to make it worse, they kept making a big deal out of how ferocious they were. Yeah, except they were like 8 inches long. Not going to keep me up at night. That and I get tired of the same old storyline on every darned documentary: racing against the clock, one setback after another, finally they get to ______, and the results are inconclusive! INCONCLUSIVE!!!
I went to bed early.