'Megalodon' Goldfish Found in Pennsylvania Waterway — and Now Officials Are Issuing an Alert to Pet Owners

A shocking discovery in Pennsylvania has prompted officials to warn pet owners about the dangers of releasing goldfish into the wild.

On February 25, 2025, the U.S. Fish and Wildlife Service (USFWS) shared an image of a massive, football-sized goldfish found during an electrofishing survey at Presque Isle State Park. Dubbed a “megalodon” goldfish, the creature is a prime example of how small, harmless pets can become invasive threats when released into natural waterways.

How Goldfish Become an Invasive Species

Why Are Goldfish a Problem?

According to the USFWS, releasing goldfish into lakes and rivers can cause serious ecological damage, including:

Uncontrolled Growth – Goldfish grow much larger in the wild, often reaching sizes of over 5 lbs.
Disrupting Ecosystems – As bottom feeders, goldfish stir up sediment, uproot plants, and muddy water, making it difficult for native species to thrive.
Outcompeting Native Fish – They steal food and habitat from native fish populations.
Rapid Reproduction – Goldfish spawn several times per season and have no natural predators, leading to unchecked population growth.
Carrying Diseases – They transmit parasites and illnesses to native aquatic life.

The Pennsylvania “Megalodon” Goldfish

Discovered during a survey in Presque Isle State Park.
Grown to an abnormal size due to an uncontrolled environment.
Evidence of how goldfish can become a long-term invasive problem.

USFWS Urges Responsible Pet Ownership

The USFWS is using this discovery to remind the public that goldfish are not meant to be in the wild.

“Someone released it, thinking they were being kind. Instead, they created an invasive problem that can last decades.” – USFWS

What to Do If You Can’t Keep Your Goldfish

Pet owners should never release goldfish into the wild. Instead, they should:

Re-home them – Find another pet owner willing to adopt.
Return them to a pet store – Many stores accept unwanted fish.
Contact local aquariums or rescue groups – Some organizations take in surrendered fish.

Goldfish & Bait Dumping Concerns

Another major concern is goldfish being used as bait.

It is legal in 16 states to use goldfish for fishing bait.
Dumping leftover bait in water introduces invasive species and pathogens.
The USFWS urges anglers to never release bait fish into waterways.

Goldfish in the Wild: A Growing Problem

The average lifespan of a wild goldfish is 41 years, according to National Geographic. Their population has already exploded in the Great Lakes, where millions are now swimming freely.