Perch Facts

Perch Profile

Students of taxonomy are renowned for their dazzling wit. One of the most popular jokes in this community is the idea that if you can’t remember what order an animal is in, just add -iformes to its name; if you don’t know its family, add -idae, and if you don’t know its subfamily, add -inae.

It’s a joke because it’s rarely true, but also because of animals like this one, for which it is: a Perciform fish in the Percidae family and Percinae subfamily. Three species of spectacular predatory fish in the genus Perca: the Perch.

Perch Facts Overview

Perch are one of the most impressive animals to be found beneath the surface of the temperate northern waterways of Eurasia. They’re medium-sized, but pack a serious punch, and when there’s nothing to hunt, they’re not above scavenging. This adaptable fish is so good at what it does that it can devastate environments that aren’t prepared for it.

But the perch isn’t just a driver of destruction, it’s also a victim of it, and at least one species, found in Lake Balkhash, is on the receiving end of a similar threat.

Interesting Perch Facts

1. Perch-like

Perch are members of the order Perciformes, which generally means “looks like a perch”. Ignoring the circular logic of this system, that places them alongside sea basses, groupers and scorpionfishes. But Perch are not marine fish, and their family, the Percidae, contains around 250 species of fresh and brackish water species of fish, the vast majority of which are in the darter subfamily, which houses over 200 of these.

In fact, the Perch subfamily, Percinae, only has about 20 species in it, and only three of these are actually perch!

There are many fish commonly referred to as perch, ranging from the petite and pretty dusky glass perch to the large and colourful Distichodus engycephalus often referred to as just “perch”. But these are not remotely related to one another, nor to the Perch genus, which is made up of just the European, the Balkhash and the yellow perch.

2. They’re widespread

Among the three of them, the European perch is the most widespread. It’s not limited to Europe, but widespread across Eurasia, and even makes it as far south as Australian waters, though it was introduced there by humans.

This is also the largest, reaching almost 4 kg in exceptional cases, but usually less than 3 kg. The Balkhash perch is found over much of Central Asia, and the Yellow perch in North America. All three are similar in appearance, and all three are natural born killers.

3. They’re predators

Perch are distinctive in several ways. Their dull green, laterally-compressed bodies are banded with dark black bars, giving them a sort of green tiger quality, and this is for the same reason tigers have a sort of orange perch quality: it’s camouflage for hunting.

Perch are mid-tier predators in a world of pike, bass and other large fish, and they hold their own well. They are incredibly strong fish, and will hunt down gobies and other smaller species with active pursuits. This keeps them out of the niche of the smaller pike, though larger ones will feed on perch if they can grab one.

Pike tend to hunt their prey from the side, and the hard spines on the back of the perch show why this is. These spines help prevent the perch from making its way into the mouth of a larger fish, and can be laid flat when hunting their own.

But perch don’t begin life as hunters, they actually have quite a varied range of feeding habits.

4. They’re also filter feeders

The relatively small yellow perch isn’t nearly as powerful as the European perch, and spends much of its early years eating zooplankton out of the water. It does this using rows of little jagged teeth lining its mouth and gills to scrape the plankton out of the water with.

They will move onto worms and other bottom-dwelling invertebrates as they get larger, and do eventually become hunters, but like all perch, they are capable of eating more or less anything, and even the largest of them will suck up worms from the sediment if the opportunity arises.

This makes them highly adaptable and opportunistic feeders and puts a huge amount of pressure on their ecosystems to keep up. This might sound like a bad thing, but it’s how all stable ecosystems are held in place.

Unfortunately, these fish have been introduced to non-native realms and there, they’re arguably not such a stabilising force. ¹

5. They’re invasive

The Balkans are a rich and biodiverse region of the planet, with a lot to worry about. Some surveys have suggested that more than 20% of the species found there are now non-native, having been brought in by mistake or on purpose by humans.

One of these species is the European perch, which has also been introduced as far as Australia and New Zealand, but even in Portugal, this species seems to be wreaking havoc.

In 2023, in one assessed region of Portugal, European perch made up 23% of specimens. Just two years later, it represented 63%. Where these fish were prevalent, almost nothing else was, and that’s a problem!

Even on a local scale, where the species is native, they can cause a lot of harm when introduced to water bodies that didn’t contain them before. Their ability to eat anything and everything makes them formidable predators and potentially very destructive animals. ^{2 3}

6. They’re doing pretty well

As you’d expect from the above, perch aren’t struggling all that much. All three species are listed as Least Concern by the IUCN, but interestingly the Central Asian native, the Balkhash perch, is in decline.

There are three reasons for this, including human development in their waterways and overfishing, but one key driver of this is the presence of introduced foreign species, and chances are, the European perch is one of them. While this species specifically isn’t officially to blame yet, relatives like the Zander, which is in the perch family, are.

So, the perch may well be both a victim and a perpetrator of invasiveness, and it remains to be seen how climate change contributes to its troubles. But for now, all three species are still pretty healthy.  

Perch Fact-File Summary

Scientific Classification

1. Sara Creque (2000), “Perca flavescens”, Animal Diversity Web.
2. Vera Sequeira(2025), “Europeanperch gaining ground: MARE researchers warn of its rapid expansion in the Tagus basin”, MARE.
3. BAKIU et al (2022), “Invasiveness assessment of European perch (Perca fluviatilis), pike-perch (Sander lucioperca) and northern pike (Esox lucius) in Albanian freshwater ecosystems by using the Aquatic Species Invasiveness Screening Kit (AS-ISK)”, Studia Marina .