He pulled an odd fish with really big teeth from a North Miami Beach pond. Was it a piranha?

A few weeks ago, Eric Estrada, an artist and ardent fly fisherman who lives in North Miami Beach, decided to visit a neighborhood pond. He hoped to hook his usual catches of peacock bass, snook or tarpon.

What he found instead was something different, something he’d never seen before. The fish hit savagely when Estrada plopped a fly into the water — “He freaking inhaled it” — and cut clean through the line.

As he threw out another fly, more fish like it swarmed. He managed to hook one and bring it to shore before releasing it. It wasn’t huge, maybe 18 inches long, but it had lots of teeth, big teeth, teeth like a piranha.

Estrada and a friend videoed the entire conquest and posted it on his YouTube channel under the title, “INVASIVE Piranhas on a FEEDING FRENZY in a Miami Pond????” It has racked up almost 3,000 views.

Happily, what he found wasn’t the infamous flesh-eating piranha. Florida’s wildlife management agency and experts believe it was almost certainly a pacu, a relative of the piranha. Both are native to the Amazon River basin. Pacu also boast impressive teeth but their diet is mostly vegetarian.

Pacu, like many other invasive freshwater species, are pulled from South Florida waterways from time to time. They often perplex anglers who think they have caught the piranha, known for their ferocious feeding frenzies. Actual confirmed piranha catches in Florida have been rare, with a few red-bellied piranha documented in a West Palm Beach pond in 2009.

As an artist, Estrada specializes in fish-themed canvas paintings, murals and apparel. He said he’s been fishing almost every day for ten years and prides himself on being able to identify species with ease.

In his video, he actually nailed it. He initially referred to the fish as a pacu. But after he reeled it in, he second-guessed himself. This particular pacu had unusually jagged teeth, and the school swarmed with force whenever a lure hit the water.

The comments on his YouTube video and social media posts showed he wasn’t alone in his uncertainty. Others also questioned, is this a pacu or a piranha? And does it matter?

State prohibits piranha

The answer to the second question is yes. They’re among the 16 freshwater exotics that are illegal to own under rules set by the Florida Fish and Wildlife Conservation Commission wildlife managers. Dozens of invasive species have settled into South Florida waterways without creating environmental havoc. Scientists fear an established population of piranha would be far more disruptive than pacu. They could attack other fish, birds and mammals.

Pacu are not natural born predators and, despite those powerful jaws, aren’t typically known to be aggressive — though once hooked, they can be formidable fighters as Estrada’s video shows.

“Pacu are sort of an oddball in terms of what they eat,” said Jeffrey Hill, fisheries extension specialist for nonnative fish under the University of Florida’s Institute of Food and Agricultural Sciences. “They eat a lot of leaves, fruits, nuts and things that just fall into the water. They will eat invertebrates and occasionally fish but they’re not a major predator.”

The most telling distinction between a pacu and a piranha is the size and shape of their teeth. Pacu teeth look like human molars and sit in straight rows, designed for munching vegetation. Piranha teeth tend to be razor-sharp triangular incisors meant to tear through flesh. Other saltwater fish known as the lookdown and moonfish are sometimes mistaken by neophyte anglers as piranha, but are unrelated.

Pacu are also larger than piranhas. Estrada said the fish he caught was about 18 inches, which is pretty small for a pacu, while piranhas average around 12 inches.

The fish Estrada caught had sharper teeth than most, but Arielle Callender, public information coordinator at the Florida Fish and Wildlife Commission, told the Miami Herald it “looks like pacu.” And as for the feeding frenzy Estrada witnessed, that frantic behavior — bee-lining for a fly — is often an indicator of human activity, rather than instinct.

“I would suspect that they are probably being fed in that pond,” Hill said. “They get used to something hitting the water to go look for food.”

Don’t judge a fish by its bite

Though pacu are not native to South Florida, they are not necessarily harmful to the region. There are no known established populations anywhere in the state, and no documented examples of threats the species pose to native wildlife.

“They’re one of the most widely introduced tropical fishes in the country, but they’re not established anywhere that we know of in the United States,” Hill said.

Pacu are a popular aquarium fish. That’s part of the reason why they end up in the United States. Their long lifespans and versatile diet make them desirable pets. But when they grow too big for their tanks, people often dump them in lakes, ponds or canals.

“A lot of the speculation is that they arose from the aquarium trade,” said Jordan Massie, a Ph.D. candidate in the Department of Earth and Environment at Florida International University. “Those intentional releases of people dumping their tanks is I think one of the main areas they spread from. There’s been records of fish that live in excess of 20 years and they can reach 30 or 40 pounds in some cases.”

Since pacu are seemingly innocuous introductions to our waterways, some researchers argue whether they are even invasive. Many prefer the term “nonnative,” since “invasive” carries with it negative connotations.

“If you live in South Florida, you’re probably aware that a lot of the things that we see around us are not native to this area,” Massie said. “The term invasive really has a lot of connotations that are attached to it, and it kind of implies that whatever animal didn’t evolve or originate here is doing harm to the ecosystem and that’s not always the case.”

The University of Georgia’s Center for Invasive Species and Ecosystem Health keeps a database of invasive species status reports by state. In Florida, there are species with tens of thousands of known recordings. For pacu, there are only 15 records listed.

Estrada had a lucky stroke with stumbling across a school of pacu — in an urban pond surrounded by apartments no less. He’s lived and fished in Miami his entire life without ever seeing one before. He may not ever come across another school again. But, if nothing else, he will take inspiration from his encounter — along with all the YouTube views.

“I’m probably gonna make a drawing of the pacu to sell as a sticker or something,” he said. “It was a crazy experience. I did not expect that.”