I’ve said it many times before, but it bears repeating — one of my favorite things about fishing is the sense of mystery it evokes.
At least a few times each fishing season, something happens that I’ve never seen before. This year, it happened on my very first trip of the spring.
Some buddies and I were fishing the Snake River. It was running high, fast and muddy, rendering bass and trout fishing difficult. So we resorted to drifting bait — and I was pleasantly surprised to get a bite fairly quickly.
The fish put up a fight, but the water was too murky to get a good look at it. Once it was netted and pulled ashore, the mystery remained — I had no idea what this creature was.
Now, I’ve caught fish in weird places before. Kokanee salmon and largemouth bass in the urban Boise River. Mackinaw trout in the South Fork Snake River. I’ve seen giant koi fish in local ponds and weather loaches in irrigation canals. But in all my time fishing fresh water, I had never before caught something and not been able to identify it.
My buddy Justin dubbed the fish a “Carplapia.” It was an apt description — the fish had the large scales and coloration of a carp, but the eyes and mouth weren’t right, and it was roughly the shape and size of the large tilapia that are known to inhabit the Snake. It definitely looked carp-like, but it wasn’t any of Idaho’s known species (common carp, which come in a few varieties, and sterile grass carp, which are stocked in certain lakes and ponds to control aquatic vegetation).
The mystery endured until I got home and did a little online research. The best match I could find was a species called the Prussian carp, which is closely related to the aquarium goldfish. I reached out to Idaho Fish and Game Regional Fisheries Manager Joe Kozfkay for a second opinion, and he arrived at the same guess — more detailed characteristics like the number of scales along the lateral line also matched the Prussian carp.
So what is a Prussian carp? Their history on our continent is a little bit muddy. The species has only been officially documented in North America for about a decade, though some records go back much farther than that. It’s impossible to say whether my Snake River catch was wild or escaped/released from someone’s aquarium or private pond. And while this was likely just an isolated incident, it’s an important reminder of the human impact on our fisheries — we need look no further than Horsethief Reservoir’s recent yellow bullhead invasion and subsequent draining and poisoning for an example of how illegally moving fish can harm an entire ecosystem.
So let’s keep our pets in their aquariums, and leave Idaho’s wild fish species where they belong. I had fun solving the case of the mystery fish, but I hope it doesn’t happen again anytime soon.
Note: If you catch a fish you suspect may be an invasive species, contact your regional Fish & Game office. They may ask for your catch in order to perform genetic testing and determine if there is a wild population.
Jordan Rodriguez has been fishing Idaho waters since he was a teen. Share your fish stories, adventures, tips and tricks at outdoors @idahostatesman.com.