Once every couple months while scrolling through my Facebook feed, I'm inspired to put on my detective cap. I see an enormous catfish with a proportionally tiny person trying to present it to a camera. The caption reads something along the lines of “Huge Catfish Caught in the [insert large US river].” The post usually includes a seemingly ridiculous weight and sometimes a short, incredible anecdote, such as “had to be pulled onto land using a pickup truck.” I never find enough evidence to validate the post as authentic, nevertheless people share them on social media. Catfish tales, however, predate social media. You may have heard the story of the enormous catfish that live your local lake or beneath the dam in the river. Many other fisheries professionals I've talked to have heard a similar story in their areas: “Divers working in the river [or lake] saw catfish the size of a Volkswagen and said they were never going back down there." While stories such as this are common, catfish tales have gained new life with the internet becoming ubiquitous and these catfish tales (right and below) can be shared by tapping on your phone.
The first thing you might think is images like these are created in Adobe Photoshop. That could be the case, but many images like these are actually real fish, just not a species found in North America and listed sizes are probably exaggerated. Most of the suspicious photos I’ve seen are of the Wels Catfish (Siluris glanis), a European species that reaches incredible sizes. The all-tackle world record Wels Catfish weighed 279 lb 9 oz and measured a little over 8 feet (Click here for details).
The Wels Catfish is classified in a different family than North American Catfishes (family Ictaluridae). Although members of several additional catfish families live in the fresh waters of Florida and Texas, only Ictaluridae is native to the freshwater systems of the US (excluding Sea Catfishes, family Ariidae, which are native and occupy fresh waters on occasion). The Wels Catfish is classified in the family Siluridae. Species from Siluridae range across Europe and Asia, but not North America. Non-native Wels Catfish populations in Europe have contributed to native species declines, prompting the US Fish and Wildlife Service to evaluate the risks associated with Wels Catfish invasions in the US (click here) The Fish and Wildlife Service determined Wels Catfish would likely generate serious impacts to ecosystems if introduced in the US and the import, sale, purchase, possession and transport of Wels Catfish is illegal under the Lacey Act. Although the business end of a Wels Catfish appears similar to a Flathead Catfish (Pylodictis olivaris), at closer examination there are many differences in anatomy when compared to North American Catfishes.
If you see a questionable photograph, it usually won’t clearly show the entire fish. Consequently, it’s good to have a couple traits to look for. Three good characteristics you can compare are the number and position of barbels (whiskers), the length of the anal fin and the presence of an adipose fin. Barbels are located around the mouth of the fish and the two families we’re interested in here (Ictaluridae and Siluridae) have different numbers of barbels. The North American Catfishes have four pairs of barbels (eight total), whereas the Wels Catfish has three pairs (six total). You’ll notice the two barbels (nasal barbels) near the nostrils (also called nares) are missing in the Wels Catfish, but are present on the Flathead Catfish below. Also, the Wels Catfish has a much longer anal fin than North American Catfishes. Finally, the Wels Catfish lacks an adipose fin. Adipose fins are fleshy fins that sit on the fish's back near the tail. They are most famously present on trout and salmon, but North American Catfishes also have them. Looking for these traits will help you determine if someone is circulating fishy fiction by claiming the fish came from North America.
Names and locations of fins and other anatomy for North American Catfishes. Image from thefishsite.cn.
Catfish from the family Siluridae like the Wels Catfish (left) have six barbels, whereas North American Catfishes such as Flathead Catfish (right) have eight. Photo Credits: left Shutterstock, right Corbin Hilling.
A 114 lb Wels Catfish (left) caught in England shows the length of the species' anal fin and lack of an adipose fin. A 57 lb Flathead Catfish from the James River, Virginia exhibits the short anal fin and fleshy adipose fin characteristic of North American Catfishes. Photo Credits: left Rodney Hills, right Corbin Hilling.
If you determine the photo is in fact one of our North American Catfishes and are still skeptical of its authenticity, you can check to see if the photo was altered using Photoshop (click here for guidance). However, there are a number of other tricks that can make fish appear larger in photos and it's easy to add a few inches or lbs to measured or estimated sizes. Everyone knows fishermen are famous for telling tall tales, but now technology is readily available to create some evidence to support them. That said, Blue and Flathead Catfish can reach astounding sizes (see How big do North American catfish get?), so these legends and social media illusions may not be as unreasonable as they may seem.