Environmental Science

Fish Urban Legends on Netflix

Posted on in Environmental Science · Featured · Ichthyology · Live Animals · People

In a new Netflix series, an Academy of Natural Sciences of Drexel University ichthyologist upacks the stories of several fish that have transcended from the water to our mythos.

Mark Sabaj, PhD, interim curator of fishes at the Academy, is showcased in the series, “72 Dangerous Animals: Latin America,” dispelling myths about three iconic sea animals: the electric eel, the payara, and the candiru, or toothpick fish.

Netflix screen shot

A frequent visitor to South America for field trips to study — and oftentimes discover — catfish, Sabaj used specimens from the Academy’s vast collection to illustrate his points on the fish as he appeared in three of the series’ 12 episodes.

While many of these fish have become urban legends or misunderstood, Sabaj laid out the real-world behaviors that might have gotten them such infamous reputations.

Episode 1: Payara

Sometimes called the wolf fish or the saber-toothed tetra, the payara is most famously known as the vampire fish. Why?

One look at its mouth provides the answer. The payara sports two, overly long teeth in its bottom jaw that look like fangs.

A close-up of the infamous jaws of the payara (vampire fish) caught in the Rio Xingu in Brazil.

“There’s no other fish in the Amazon basin that has teeth quite like a payara,” Sabaj explains in the episode. “They’re quite formidable, extremely long fang-like teeth that it uses to immobilize its prey when it strikes. They get pretty long.”

Their fangs can reach 15 centimeters in length. For a fish that might get up to 117 centimeters in total body length, that’s roughly an eighth of their size. So, they’re not exactly working with baby teeth.

“They’ll hang in pools, in still water, next to fast-flowing rapids,” said Sabaj. “They’re a lie-in-wait-then-lunge predator. The strike of these fish is in a millisecond. It’s so fast.”

Sabaj especially stressed that strike.

“You really get an appreciation for the power of their strike when you fish for these things,” he said. “They move so quickly, and it can be so large, they just thrash at (their target) … they hit like a ton of bricks.”

However, despite their fearsome look, payara haven’t been linked to very many attacks on humans.

Episode 8: Electric eels

Electric eels don’t glow like neon bulbs, as cartoons would have you believe, but they still pack a punch.

Reaching up to 860 volts, an electric eel’s shock is more than five times the zap you’d get if you stuck a finger in a wall outlet. But why did it evolve to have this electrical power?

Sabaj using the method for catching electric eels without getting shocked.

“Its eyes are really small. Its not really using eyesight much for its hunting,” Sabaj says in Episode eight. “Basically, what it’s using is electric-location. It will give off these high frequency bursts, doublets or triplets. If there’s prey items hiding in its environment, it will cause them to twitch, then it will know where it is.”

Once it locates prey, that’s when the eel’s big shock comes.

“And now it gives off a full high-frequency, high-voltage charge that completely immobilizes its prey and then, basically, it just swallows it whole,” Sabaj continues. “It causes, basically, a whole body muscle contraction. And the fish just freezes.”

Human deaths from electric eel shocks are less electrocution and more drowning due to immobilization caused by the shock.

Episode 11: Candiru

A small catfish nicknamed the “toothpick fish,” Candiru are tied to a particularly intimate urban legend.

A candiru specimen from the Academy. The reference line is a centimeter long.

As the story goes, a fisherman immersed in the Amazon River was urinating when the fish swam up and into his urethra.

This is probably the time to mention that this particular fish has backwards-facing spines. So, pulling it out likely would be an option. However, Sabaj isn’t sure the story is true. And, if it is, he thinks the fish was confused.

“They don’t want to do that,” Sabaj says. “If [it did], that fish is clearly making a mistake.”

Candiru typically enter fish through their gills and attach themselves inside to feed.

Sabaj only sees one way this story could be true. Since fish’s gills expel waste and jets of water, it’s possible that a human urinating might be confused for a fish gill.

“One would assume that there’s some aspect of urinating in the water that mimics some aspect of [fish gills] and the candiru is just getting a similar cue, but from a completely unrelated source.”

 

Post by Frank Otto

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