Catfish

Catfish are many kinds of fish.

They have whiskers like a cat. These whiskers help them find food. Many catfish live on the bottom. They use their whiskers to taste things in the water.

Most catfish do not have scales. Their skin is smooth. Some have hard plates like armor.

Some catfish are very big. They can grow quite large. Other kinds are very tiny.

Many people catch these fish for food. They are very important to us.

Catfish are a large group of fish. They are named for their barbels. These are long parts that look like cat whiskers.

Most catfish live on the bottom of the water. They often have flat heads to help them dig. Many catfish do not have scales. Their skin is often smooth. Some species have hard plates called scutes. These plates act like armor to protect them.

Catfish use their barbels to find food. They have special sensors to taste and smell the water. Because they rely on taste, many have very small eyes. Some even live in dark caves without eyes at all.

These fish come in many sizes. The Mekong giant catfish is one of the largest. Other types are very tiny. Some catfish also have sharp spines on their fins. These spines can lock in place. Some species even use these spines to sting.

Many people catch catfish for food. Some are even raised on farms. Others are kept in tanks as pets.

Catfish are a huge and diverse group of fish. They belong to an order called Siluriformes. Most people know them because of their barbels. These are long parts that look like a cat's whiskers.

Not every single catfish has these long whiskers. However, these barbels are a very important part of how they live. They help the fish find food in dark or murky water. This makes them a very special group of animals to study.

Many catfish live on the bottom of rivers or lakes. They are often negatively buoyant. This means they tend to sink instead of floating. They have heavy, bony heads to help them stay down.

Most have a cylindrical body with a flat underside. This shape helps them feed along the floor of the water. Some even have a suckermouth to hold onto rocks in fast water. They use suction or gulping to eat rather than biting.

Scientists study how these fish have changed over time. They look at the skull and the swimbladder to group them. For example, the maxilla is a bone that holds teeth. In catfish, this bone changed into the base for their barbels. This change means they cannot move their mouths forward like a carp.

This is a great example of how body parts can change for a new job. Even their skin has changed in interesting ways. Some have smooth skin, while others have bony armor called scutes.

Catfish come in many different sizes and places. The Mekong giant catfish from Southeast Asia is one of the largest. The wels catfish lives in Eurasia and can grow very big.

In the United States, people call them many names like "mud cat." In July 2009, an 11-year-old girl caught a huge catfish in Spain. It weighed 70 pounds! Other catfish, like the tiny candiru, are very small. This shows how much variety exists in one group of fish.

Many things in your life might link to catfish. You might see them in a pet store aquarium. Small types like Corydoras are very popular pets.

You might also see them on a menu at a restaurant. Many large species are farmed or fished for food. Some people even use them to study how animals defend themselves. Most catfish have sharp spines on their fins. These spines can lock in place to protect the fish. Some species even use these spines to deliver a sting.

Catfish belong to the order Siluriformes, a diverse group of ray-finned fish. They are most famous for their barbels, which are whisker-like sensory organs. While not every species has prominent barbels, they are a defining feature for many.

Unlike most other fish, Siluriformes lack scales. Instead, they possess either smooth, mucus-covered skin or protective armor-plated bodies. Scientists classify this order based on specific skull features and the structure of the swimbladder. This group is incredibly varied, ranging from tiny parasites to some of the largest freshwater fish in the world.

Most catfish are benthic feeders, meaning they live and hunt on the bottom. They are often negatively buoyant, which means they tend to sink rather than float. This is caused by a reduced gas bladder and a heavy, bony head.

Many species have a cylindrical body with a flattened ventrum, or underside. This shape helps them stay stable while feeding on the substrate. Some families, such as Loricariidae, have evolved a specialized suckermouth. This allows them to fasten themselves to objects in very fast-moving water.

Instead of biting or cutting prey with teeth, most catfish use suction or gulping to eat.

The skin of a catfish provides different types of protection. Some species rely on cutaneous respiration, where they breathe through their mucus-covered skin. Others have evolved bony plates called scutes for armor. In the genus Sisor, these plates are often supported by vertebral processes. In the subfamily Doumeinae, the armor is formed entirely by expanded vertebral processes.

Other species, like the doradids, possess lateral armor made of thickened ossicles. This variety in skin structure shows how different species have adapted to their specific environments.

Catfish use complex sensory systems to navigate and find food. Their barbels are highly sensitive to chemicals in the water. Many larger species have chemoreceptors across their entire bodies, including their barbels. This allows them to "taste" and "smell" their surroundings to locate prey.

Because these chemical senses are so vital, many catfish have very small eyes. Some species living in underground caves have lost their eyes entirely. They also possess a Weberian apparatus, which is a structure that connects the swimbladder to the ear. This allows for improved hearing and sound production.

Defense is another major aspect of catfish biology. Most catfish possess a strong, hollow, bony spine on their dorsal and pectoral fins. They can lock these spines into place to stick outwards. This makes it difficult for predators to swallow them. In about half of all catfish species, these spines are venomous. Glandular cells in the skin cover the spines and produce a stinging protein. In the species Plotosus lineatus, a sting from these spines can be fatal to humans. This makes Siluriformes the vertebrate order with the largest number of venomous species.

The size range within Siluriformes is massive. The Mekong giant catfish from Southeast Asia is one of the largest species alive. In contrast, some members of the Trichomycteridae family reach maturity at only 10 millimeters.

Historical records and mythology often describe the wels catfish as having astounding proportions. While many of these stories are unverified, real specimens are quite large. For example, a wels catfish weighing 70 pounds was caught in Spain in 2009. In the Missouri River, a blue catfish weighing 100 pounds was caught in 2010.

Catfish have significant connections to human industry and hobbies. Many large species, such as Pangasius and Clarias, are farmed or fished commercially for food. Smaller species, like those in the genus Corydoras, are very popular in the aquarium hobby. However, this hobby has also led to the spread of invasive species. For instance, plecos from the genus Pterygoplichthys have become prolific invasives in many areas. This demonstrates how the movement of species can impact entire ecosystems.