The article says it was a Pacu that was caught. Pacu eat more aquatic plants than anything else. They will eat bait fish and insects on occassion though. I guess they are opportunistic. I have seen fishing shows where they fish for them with nuts and berries.
I was fishing Landen Lake several years ago with my nephews and there were a couple guys fishing night crawlers on the bottem for cats and caught 3 praranah. 3 IN LANDEN LAKE It was crazy but they were the real deal. about a pound or so. I called the dnr and they told they were most likely pets realesed (illegally) into the lake and they would not winter over. The guys that cought them kept them and was going to fry them up. They are staple food source along the amazon river basin. I have seen them cooked over a fire wraped in banana leaves (I think it banana) Very intersting National Geograhic program on the amazon and people that realy on the river for sustinace. S