Piranhas in Malaysia? 7 facts about this much-feared fish

Few fish have been handed a worse public image than the piranha. Mention the name and many people picture a river boiling with razor-toothed fish stripping flesh from bone in seconds.

So when a fish suspected to be a piranha was caught at Klau Dam in Raub, Pahang on Aug 26, it was hardly surprising that social media lit up.

The fisheries department has since said there is no evidence of an established or breeding piranha population in the dam, and no further suspected fish had been caught as of Sept 15.

The fish itself was no longer available for examination, but photographs and video were judged to have features consistent with the genus Pygocentrus, one of the best-known piranha groups.

So, how much of their fearsome reputation is deserved? Here are seven fascinating facts about this supposedly fearsome fish.

1. Piranhas are not native to Malaysia

Piranhas are freshwater fish native to South America, especially river systems connected to the Amazon basin. That means any piranha found in Malaysian waters would be an introduced species rather than part of the natural ecosystem.

This is why the fisheries department has warned against releasing alien fish into rivers, lakes and reservoirs. Even an exotic pet that seems harmless in an aquarium can create ecological problems if it survives and reproduces in the wild.

For now, there is no evidence that this has happened at Klau Dam.

2. Yes, they eat flesh – but that is only part of the menu

Piranhas do have sharp teeth and some species certainly eat flesh. But their diet is much broader than pop culture would have you believe.

Red-bellied piranhas, for example, may feed on small fish, bits of flesh, insects, aquatic invertebrates and even plant material such as fruit. A significant part of their diet can also come from nipping pieces from the fins of larger fish.

So while “flesh-eating fish” is not exactly false, it leaves out a lot of context.

3. They are far less likely to devour people than films suggest

Scientific reviews have found very little evidence for the classic image of piranhas swarming and consuming healthy humans. Most documented injuries involve a single bite, often to bathers or swimmers, and are thought to be linked to territorial behaviour or protection of nests and young.

A recent review of more than 700 reported piranha bites in Brazil found that over 80% were mild, with many involving isolated “punch-out” wounds rather than frenzied attacks.

That does not make piranhas harmless, but it does put the threat in perspective.

4. Some ‘man-eating’ cases involved people who were already dead

This is one of the stranger facts behind the legend.

A scientific review of documented incidents found that several cases in which piranhas were said to have “eaten” humans involved people who had already died from causes such as drowning or heart failure before the fish began scavenging.

That is very different from a healthy swimmer being overwhelmed by a school of hungry fish.

5. Their teeth really are impressive

Piranhas do have a formidable bite: their triangular, interlocking teeth are designed for slicing and shearing, which helps explain why even a single bite can cause a distinctive chunk-like wound.

The teeth are one reason their reputation has endured so successfully, but the anatomy does not mean they are constantly hunting large animals – or people.

6. Hollywood has done wonders for their bad reputation

Piranhas have enjoyed a surprisingly long career as horror villains. Best-known film series include “Piranha” (1978), “Piranha II: The Spawning” (1982), “Piranha 3D” (2010) and, mind-bogglingly, “Piranha 3DD” (2012).

The original arrived in the wave of creature features that followed “Jaws”, replacing the shark with something smaller but, on screen at least, considerably more numerous.

And there is a nice piece of film trivia tucked into the franchise: “Piranha II” was an early directing credit for James Cameron, years before “Titanic” and “Avatar”.

No wonder generations of moviegoers grew up regarding any vaguely toothy freshwater fish with suspicion.

7. The real issue in Malaysia may be ecological, not cinematic

The Klau Dam report is intriguing, but so far it points to one suspected fish, not an invasion.

The fisheries department says continued monitoring has not found further evidence of piranhas or related safety incidents, and has even released a visual comparing it to the more innocuous ikan pacu.

So, again, this makes the bigger concern less about swimmers being eaten and more about what happens when exotic species are released into local waterways. Introduced fish can compete with native species, prey on them, alter food webs and potentially affect biodiversity if they become established.

For anyone who catches an unfamiliar exotic fish, the advice from the department is simple: do not release it back into the water. Keep the specimen if possible, and contact the nearest fisheries office so it can be properly examined.

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