Considering the humble Nile perch, Austrian filmmaker Hubert Sauper asks a seemingly absurd question: Is it possible that a mere fish has destabilized much of central Africa? Incredibly, the answer appears to be yes. The Nile perch, a large, relatively bone-free freshwater fish is not native to Lake Victoria, but was artificially introduced sometime in the late '50s. Since then, this hardy predator has forever altered the balance of Lake Victoria's ecosystem, while serving as the cornerstone of a massively lucrative fishing industry that has completely transformed the economies of the surrounding nations — and not for the better. True, this artificial industry has brought jobs to lakeshore towns — one factory in Mwanza, Tanzania, employs 1000 locals — but the main beneficiaries of this abundance of fish are the foreign-owned and -operated fisheries where the perch are cleaned, gutted and filleted, then flown out to Europe on enormous Russian cargo planes at a astounding rate of 500 tons a day. What few benefits the Nile perch has brought to a native people plagued by famine, poverty and civil war have come at a terrible price. Abandoning their dying drought-stricken farms in the Tanzanian hinterlands, men now flock to the shores of Lake Victoria in search of those precious jobs. Meanwhile, desperate, HIV-stricken women back at home turn to prostitution to avoid starving to death and, after relocating to the same fishing camps that have attracted their menfolk, inadvertently spread the disease to the fishermen who then bring the virus back to their villages. And just in case you might think this miracle of the fishes might alleviate famine conditions, Sauper points out that the Nile perch is actually far too expensive for the millions of locals who are reduced literally to eating garbage. In the film's most horrific sequence, Sauper follows truckloads of maggot-ridden fish heads to a Mwanzan backwater where they'll be dried, fried and — gag — eaten. Throughout the film, which not only surveys workers from all echelons of the fishy business, but the sex industry that has sprung up around it, Sauper persistently asks a question no one dares address truthfully: What, exactly, are those "empty" cargo planes bringing in to Tanzania? The answer will shock you. By the time the last domino has fallen, it's hard to think of a facet of African life that hasn't been tainted by the introduction of the seemingly innocuous Nile perch. Far more than a mere fish tale, Sauper's dark, devastating documentary profiles a socio-ecological nightmare with unimaginable consequences, and it's one of the best films yet about the ugly reality of the global marketplace.