What is a Trash Fish?

Mary McMahon
Mary McMahon

A trash fish is a fish that does not have food value. “Trash” is actually a bit misleading, as trash fish can have commercial value and they may play an important role in the ecosystem. Furthermore, some are of interest to sport fishermen. These fish are also known as “rough fish” in some regions of the world.

Many "trash fish" actually have commercial value.
Many "trash fish" actually have commercial value.

Definitions of what constitutes a trash fish are quite variable. Over time, attitudes about fish species may evolve. The lobster, for example, was once regarded as fodder for only the most desperate of the lower classes, and is today a delicacy in many regions. Likewise, carp is a trash fish in the United States, but is highly prized in Asia as a food fish and in Europe as a sport fish. These varying attitudes reflect availability of different fish species; more plentiful fish are more likely to be treated as trash fish, and when popular fish decline, people look for substitutes and may turn to fish they previously rejected.

Although such fish are not consumed in the markets where they are caught, they can still have uses. Aquaculture farms need steady supplies of fish and fish is also included in animal fodder. When trash fish are caught, they can be sold to dealers who will process them for sale to farmers, as well as pet food manufacturers. These fish can also be used in the production of fertilizers.

Trash fish can also be important figures in the ecosystem. Even if a fish has no food value, cannot be sold on the market, and is of no interest to sport anglers, it can still have environmental value. Aquatic ecosystems are complex and highly interconnected. A bottomfeeding fish like a lamprey that is not desirable to humans might contribute to water quality and support conditions that allow more popular fish species to thrive. Disrupting the biodiversity of an ecosystem can result in a collapse of a fishery.

Very few fish are regarded universally as trash fish. Culinary tastes vary widely throughout the world and one person's trash may be another person's delicacy. Desperation sometimes spawns creativity and some very famous dishes actually have their origins in finding clever ways to use these types of fish. Species that people may not be interested in eating fresh may be preserved and seasoned in some regions, and the fish sauces of Asia can be produced with less commercially valuable fish species.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

You might also Like

Readers Also Love

Discussion Comments


@Mor - You can't just blame greed for the mismanagement of fish stocks around the world. That definitely plays a part, but I think for the most part it's no different from what you just described with the trash fish.

If certain companies decide to no longer fish in unsustainable ways, catching huge amounts of trash fish bycatch as well as their commercial take, they will probably have to spend more money to fish in better, more sustainable ways.

That means companies willing to continue using the same methods will have an advantage and will fill the "holes" left behind by the other companies, so the problem doesn't exactly go away.

What they need is decent regulation, so that trash fish can be seen for their real value and every kind of fish stock can be protected.


It's a shame that trash fish are labeled the way that they are. All fish have an environmental impact, whether for the better or for the worse. Most of the time it's for the better, unless they've been moved to somewhere they aren't supposed to live.

Trash fish are caught as bycatch, which is the fish that are caught along with the target fish.

And in large commercial operations, there often isn't enough care taken to make sure these fish are put back in the water in good condition.

This makes a huge impact on fish stocks, as trash fish are often what the targeted fish feed on, or they might be predators that keep competing fish in check. By removing them from the system, along with the targeted fish, you disrupt the ocean ecosystem in ways that can lead nowhere good.

There are places in the world where they've depleted the fish stocks so badly that so called trash fish have thrived in the holes left by the commercial stocks, and filled those holes so completely there's no chance the commercial stocks will ever be able to recover.

Moderation is the key, but unfortunately when people have dollar signs in their eyes, they can't see it.


Koi fish are another type of fish that could be labeled as trash fish in some places but are considered a delicacy in others.

I know in New Zealand they are the worst kind of pest, as they multiple quickly in the waterways and force out native and commercial species.

And there is no widespread use for them in New Zealand except as ornamental fish.

They are generally only in the waterways because they either somehow escaped from ornamental ponds or they were dumped there.

But Asian immigrants from several countries think of koi fish as a food source and will catch them to eat. Apparently it doesn't taste too bad, but they have a lot of tiny bones which can be annoying.

I guess one person's trash is another's treasure and frankly, since the fish are an environmental disaster, the more people eat the better.

Post your comments
Forgot password?