a 10 pounder I imagine would be a good fight. I read in an igfa book that they are good cgamefish that are strong fighters. They're also agressive and can be caught on plugs bigger than them. They are also everywhere including "harbors" near villages in the Amazon that have no other fish and are attracted by the people cleaning their catch and tossing the scraps into the water. I saw an animal planet thing on Piranhas with Nigel Marvin. He fished with a guide in ne of those ares and caught a Red Belly, a Black Rhom, and a Sharp Snouted.