Animals in Freshwater Biome Rivers

A freshwater aquatic biome, a category that includes rivers, has relatively low to nonexistent salt content. Animals and plants found in freshwater biomes, like rivers, have adapted to life there. Most of them would not be able to survive in aquatic biomes with high salt content, like oceans and seas.

Fish

• The river biome is the natural habitat of many species of fish. They include catfish, bass, minnow, carp, gar and suckers. Other types of freshwater river fish include American eel, rainbow trout and paddlefish. Freshwater river bass are divided into black bass and true bass. Black bass include spotted bass, largemouth bass and Guadalupe bass. True bass include striped bass, white bass and yellow bass. Catfish are big river fish which are found in tributaries and main channels of river systems. The piranha is found in some rivers, including the Amazon in Brazil.

Reptiles

• Reptiles are classified as cold-blooded animals due to the fact that they cannot regulate their body temperature. As such, they rely on various external sources to keep warm. Most of them bask in the sun when the water or weather becomes too cold. The main reptilian species found in rivers are turtles and crocodiles. Crocodiles feed on fish and on land animals. They usually hunt by stealth when they are in the water; they remain submerged, resembling pieces of log, until they lunge at their prey.

Amphibians

• Amphibians are those animals capable of living in both water and on land. Some of them start their lives in the water and mature into adults that can breathe air. Examples of freshwater river amphibians include salamanders, frogs and mudpuppies. Frogs usually spawn in water, including rivers. They also spawn in a variety of other habitats where water is available. Their tadpoles usually develop inside water.

Mollusks

• Mollusks are animals with hard outer shells that protect a soft inner body. They are found in any freshwater habitat, including rivers. Examples of mollusks include snails, clams and mussels. Some freshwater river snails include the spiny river snail and geniculate river snail. River mussels include the pocketbook mussel, blacksa mussel, mapleleaf mussel and Wabash pigtoe. Mussels feed on particles of food in flowing river currents. They serve an important function in the freshwater ecosystem by helping filter out waste particles.