An Aurora man has quite a fish story to tell his grandchildren.Burnis Jones was fishing in the Cherry Creek Reservoir with a friend this morning when he reeled in a fish he'd never seen before. At first he was told it was a piranha.Jones took the fish to four different bait shops before someone identified it as a piranha, but he didn't believe them."Piranhas don't get that big. That's the first thing that went through my mind," said Jones.So someone took it to the Colorado Division of Wildlife where it was identified as a pacu. A pacu is a South American tropical fish from the same general family as a piranha although not nearly as ferocious."A couple distinguishing features between a piranha and a pacu is definitely the bottom jaw," said Department of Wildlife hatchery chief Rich Kolecki.The under bite would be more pronounced and the teeth would be much sharper if it were a piranha.Doug Worthing said he wouldn't want to get in the water with a piranha."It's like swimming with barracudas and sharks, anything that draws blood," said Worthing.The Department of Wildlife said while the pacu eats mainly plants, it doesn't belong in the Cherry Creek Reservoir."It may not be just because it eats the wildlife in Colorado, it could be that it has virus or bacteria that this part of the world isn't used to," said Tyler Baskfield of the Department of Wildlife.Jones said the only reason he didn't throw the fish back was because his friend told him not to so they could find out what kind of fish it was.Wildlife officials said it's likely that the fish outgrew someone's aquarium and they unloaded it go in the reservoir, which is illegal.