Large Pacu at the Shedd Aquarium in Chicago. Photo: I, Omnitarian

Here’s another fish story via the Schuylkill Action Network: An article in last weekend’s Mercury reported that a 22-year-old fisherman caught a pacu—a South American freshwater fish related to the piranha—in the Schuylkill River near Pottstown on Aug. 1. The angler, Josh Carmean, initially thought he’d hooked a two-pound catfish until he examined the fish’s teeth.

“Pacu and piranha have similar teeth, but their jaw alignments are different. The piranha also have pointed, razor-sharp teeth with a pronounced underbite, while pacu have squarer and more straighter teeth with a less severe underbite. Also, sources reveal, the pacu are much larger than piranha, some reaching up to 60 pounds or more in the wild.

Pacus are also known to ‘eat anything,’ according to Deep Sea World zoological manager Matthew Kane. Though not the aggressive carnivores like piranha, the pacu’s crushing jaw system can be hazardous. They are often sold to home aquarium owners as ‘vegetarian piranhas.’

The pacu may have gotten a bad name as a result of owners illegally releasing them into wild waterways. Once in those waterways, like the Schuylkill River, they can dominate other species vying for available food and other resources, even displace some by introducing exotic parasites or diseases.”

Pottstown is upstream from Philadelphia on the Schuylkill, the same river that will host the 2011 Philly Fun Fishing Fest on September 10. Did we mention that registration is free and now open? Might there be a special award to the angler who lands a pacu?