The term fish is used to refer to an incredibly diverse group of animals. There are certain similarities they share, but almost all of them have some sort of exception. For example, all fish are vertebrates, but hagfish technically don't have a spine. This means the taxonomy of fish (i.e. how they are grouped into types) can be difficult to organize. There are two very general categories of fish: marine and freshwater fish. Marine fish live in the salty waters of the world's oceans, whereas freshwater live in desalinated rivers, lakes and other bodies of water.
At AnimalWised we are going to look at why fish are grouped like this, as well as the different types of freshwater fish. We provide some photos of these fascinating creatures, facts about their behavior and also show you some you need to be wary of.
Difference between freshwater and saltwater fish
In order to discuss the difference between types of marine and saltwater fish, we first need to define the term homeostasis. This will help us create the distinction between the two. Homeostasis is the process by which a living organism keeps its vital biological processes stable, despite any changes which may occur in their environment. It is essentially a state which keeps physical and chemical changes in equilibrium. An example is maintaining body temperature within a certain range.
Different types of freshwater fish are able to maintain this equilibrium more easily since their external environment is more similar to their internal tissue. This is because the salinity of freshwater is not very high. This means water can pass through the fish's gills and leave the operculum with less resistance. Additionally, they have well-developed kidneys to properly filter the water.
On the other hand, the excessive salinity of marine waters causes greater difficulty. When they breathe through their gills, a large amount of water is expelled. This is why saltwater fish take in a lot of water. Their kidneys are then needed to expel the leftover salt and maintain homeostasis.
Dangerous freshwater fish
If we were to think of dangerous fish, our minds might go to the oceans where great white sharks and other intimidating sea creatures exist. However, in certain rivers, lakes and wetlands of the world lurk highly dangerous types of freshwater fish which can even cause death to people of the region. These fish include:
Piranha (subfamily - Serrasalminae)
Piranha are a type of freshwater fish which inhabit the rivers of South America, such as the Amazon River and its tributaries. Although its jaws are very strong, a single piranha will be unlikely to inflict much damage. A large school of piranha, however, can kill even large animals trapped in the river in a matter of minutes.
Electric eel (Electrophorus electricus)
Despite their name, the electric eel if not actually an eel. They live in South America in the Amazon and Orinoco rivers. They prefer muddy areas such as mudflats. It doesn't even matter if the water is poorly oxygenated since they breathe air. Its danger lies in the fact the fish can create electrical energy. In order to hunt food, defend against predators and communicate, the electric eel can produce strong electric shocks generated from their head. These shocks can be sustained for more than a minute and they are strong enough to kill a person.
Alligator gar (Atractosteus spatula)
This fish is distributed throughout the eastern part of Central America. They can reach more than 3 meters in length and exceed 200 kilograms in weight. Its upper jaw contains two rows of very sharp teeth which have been used to attack humans.
175+ types of freshwater fish in the United States of America
There are many fish in the freshwaters of the United States, but not all of them are native. Explorers who brought back species from far away lands or individuals who have brought in exotic species as pets can introduce fish which don't belong in their ecosystem. The results of these introductions can be catastrophic to native populations. Still, many manage to thrive.
There are some fish on this list which are incredibly common. There are species of trout, madtom, shiner and catfish which have large populations. Many are still fished by anglers, some of them are even put into fish farms and fishing lakes. However, whether due to overfishing, habitat destruction, water pollution or natural reasons, some fish populations have dwindled. Some types of freshwater fish species once thriving in America are now extinct.
Here we bring you just a selection of some of the hundreds of types of freshwater fish currently living in the USA. Some of them are marked as rare, but populations change and some may have recovered populations or some are no longer evidenced by conservationists:
- Alabama hog sucker (Hypentelium etowanum)
- Alaska whitefish (Coregonus nelsonii)
- Amazon molly (Poecilia formosa)
- American paddlefish (Polyodon spathula)
- Arctic cisco (Coregonus autumnalis)
- Arctic grayling (Thymallus arcticus)
- Arkansas darter (Etheostoma cragini)
- Arroyo chub (Gila orcuttii)
- Ashy darter (Etheostoma cinereum)
- Banded killifish (Fundulus diaphanus)
- Banded sunfish (Enneacanthus obesus)
- Bandfin shiner (Luxilus zonistius)
- Barrens topminnow (Fundulus julisia) [rare]
- Beaded darter (Etheostoma clinton)
- Bigeye chub (Hybopsis amblops)
- Bigmouth chub (Nocomis platyrhynchus)
- Black bullhead catfish (Ameiurus melas)
- Black madtom (Noturus funebris)
- Blackspotted topminnow (Fundulus olivaceus)
- Blacktail redhorse (Moxostoma poecilurum)
- Blacktip shiner (Lythrurus atrapiculus)
- Bleeding shiner (Luxilus zonatus)
- Blind cave fish (Astyanax mexicanus)
- Blotchside longperch (Percina burtoni)
- Bluefin killfish (Lucania goodei)
- Bluegrass darter (Etheostoma jimmycarter)
- Bluehead chub (Nocomis leptocephalus)
- Bonneville cutthroat trout (Oncorhynchus clarki utah)
- Bonneville whitefish (Prosopium spilonotus)
- Brindled madtom (Noturus miurus)
- Bull chub (Nocomis raneyi)
- Burbot (Lota lota)
- Burrhead shiner (Notropis asperifrons)
- Caddo madtom (Noturus taylori) [rare]
- Cardinal shiner (Luxilus cardinalis)
- Cedar sculpin (Cottus schitsuumsh)
- Central mudminnow (Umbra limi)
- Channel catfish (Ictalurus punctatus) [most common NA catfish)
- Checkered madtom (Noturus flavater)
- Cherryfin shiner (Lythrurus roseipinnis)
- Chihuahua chub (Gila nigrescens)
- Chihuahua shiner (Notropis chihuahua)
- Chiselmouth (Acrocheilus alutaceus)
- Choctaw bass (Micropterus sp. cf. punctulatus)
- Clear chub (Hybopsis winchelli)
- Coastrange sculpin (Cottus aleuticus)
- Colorado River cutthroat trout (Oncorhynchus clarki pleuriticus)
- Comanche Springs pupfish (Cyprinodon elegans) [rare]
- Conasauga logperch (Percina jenkinsi)
- Coppercheek darter (Nothonotus aquali)
- Creek chubsucker (Erimyzon oblongus)
- Crescent shiner (Luxilus cerasinus)
- Cui-ui (Chasmistes cujus)
- Cumberland darter (Etheostoma gore)
- Cumberland darter (Etheostoma susanae) [rare]
- Cutthroat trout (Oncorhynchus clarkii)
- Cypress minnow (Hybognathus hayi)
- Death Valley pupfish (Cyprinodon salinus)
- Desert dace (Eremichthys acros)
- Desert pupfish (Cyprinodon macularius) [rare]
- Devils River minnow (Dionda diaboli)
- Diamond darter (Crystallaria cincotta) [rare]
- Doapa dace (Moapa coriacea) [rare]
- Duskystripe shiner (Luxilus pilsbryi)
- Eastern blacknose dace (Rhinichthys atratulus)
- Eastern mudminnow (Umbra pygmaea)
- Eastern sand darter (Ammocrypta pellucida)
- Elegant madtom (Noturus elegans)
- Emerald shiner (Notropis atherinoides)
- Flame chub (Hemitremia flammea)
- Flat bullhead (Ameiurus platycephalus)
- Fountain darter (Etheostoma fonticola)
- Freckled darter (Percina lenticula)
- Freckled madtom (Noturus nocturnus)
- Gila chub (Gila intermedia)
- Gila longfin dace (Agosia chrysogaster chrysogaster)
- Gila topminnow or charalito (Poeciliopsis occidentalis)
- Gila trout (Oncorhynchus gilae) [rare]
- Glassy darter (Etheostoma vitreum)
- Golden trout (Oncorhynchus aguabonita)
- Green sunfish (Lepomis cyanellus)
- Guadalupe bass (Micropterus treculii) [rare]
- Guadalupe roundnose minnow (Dionda nigrotaeniata)
- Headwater chub (Gila nigra)
- Highfin carpsucker (Carpiodes velifer)
- Highland darter (Etheostoma teddyroosevelt)
- Hoosier cavefish (Amblyopsis hoosieri)
- Hornyhead chub (Nocomis biguttatus)
- Humboldt cutthroat trout (Oncorhynchus clarkii humboldtensis)
- Independence Valley tui chub (Siphateles bicolor isolata)
- Ives Lake cisco (Coregonus hubbsi)
- June sucker (Chasmistes liorus) [rare]
- Kanawha darter (Etheostoma kanawhae)
- Klamath largescale sucker (Catostomus snyderi)
- Kokanee salmon (Oncorhynchus nerka)
- Lahontan cutthroat trout (Oncorhynchus clarkii henshawi)
- Lake chub (Couesius plumbeus)
- Lake sturgeon (Acipenser fulvescens)
- Largemouth bass (Micropterus salmoides)
- Least killfish (Heterandria formosa)
- Lined chub (Hybopsis lineapunctata)
- Longjaw minnow (Ericymba amplamala)
- Longnose darter (Percina nasuta)
- Longnose sucker (Catostomus catostomus)
- Lost River sucker (Deltistes luxatus) [rare]
- Manantial roundnose minnow (Dionda argentosa) [rare]
- Margined madtown (Noturus insignis)
- Mayan cichlid (Mayaheros urophthalmus)
- Mississippi silvery minnow (Hybognathus nuchalis)
- Mountain madtom (Noturus eleutherus)
- Mountain redbelly dace (Chrosomus oreas)
- Mountain whitefish (Prosopium williamsoni)
- Muskellunge (Esox masquinongy)
- Neosho madtom (Noturus placidus)
- Northern brook lamprey (Ichthyomyzon fossor)
- Northern leatherside chub (Lepdomeda copei)
- Northern pike (Esox lucius)
- Oregon chub (Oregonichthys crameri)
- Ouachita madtom (Noturus lachneri) [rare]
- Owens pupfish (Cyprinodon radiosus) [rare]
- Ozark bass (Ambloplites constellatus)
- Ozark chub (Erimystax harryi)
- Ozark madtom (Noturus albater)
- Ozark shiner (Notropis ozarcanus)
- Paiute cutthroat trout (Oncorhynchus clarkii seleniris)
- Paleback darter (Etheostoma pallididorsum)
- Peppered chub (Macrhybopsis tetranema)
- Plains killfish (Fundulus zebrinus)
- Prairie chub (Macrhybopsis australis)
- Pretty shiner (Lythrurus bellus)
- Railroad Valley springfish (Crenichthys nevadae) [rare]
- Rainbow trout (Oncorhynchus mykiss)
- Red River pupfish (Cyprinodon rubrofluviatilis)
- Redband darter (Etheostoma luteovinctum)
- Redtail chub (Nocomis effusus)
- Riffle minnow (Phenacobius catostomus)
- Rio Grande chub (Gila pandora)
- River carpsucker (Carpiodes carpio)
- Rock bass (Ambloplites rupestris)
- Rosyface chub (Hybopsis rubrifrons)
- Sacramento blackfish (Orthodon microlepidotus)
- Sacramento splittail (Pogonichthys macrolepidotus)
- Saratoga Springs pupfish (Cyprinodon nevadensis nevadensis)
- Shadow bass (Ambloplites ariommus)
- Sharphead darter (Etheostoma acuticeps)
- Shoal chub (Macrhybopsis hyostoma)
- Shortjaw cisco (Coregonus zenithicus) [rare]
- Shortnose gar (Lepisosteus platostomus)
- Shortnose sturgeon (Acipenser brevirostrum)
- Shortnose sucker (Chasmistes brevirostris) [rare]
- Shoshone sculpin (Cottus greenei)
- Silver lamprey (Ichthyomyzon unicuspis)
- Slender madtom (Noturus exilis)
- Smallmouth bass (Micropterus dolomieu)
- Smoky madtom (Noturus baileyi)
- Sonora sucker (Catostomus insignis)
- Southern sand darter (Ammocrypta meridiana)
- Spotted chub (Erimystax x-punctatus)
- Starhead topminnow (Fundulus dispar)
- Stonecat (Noturus flavus)
- Tadpole madtom (Noturus gyrinus)
- Texas cichlid (Herichthys cyanoguttatus)
- Toothless blindcat (Trogloglanis pattersoni)
- Turquoise darter (Etheostoma inscriptum)
- Umpqua chub (Oregonichthys kalawatseti)
- Umpqua pikeminnow (Ptychocheilus umpquae)
- Utah chub (Gila atraria)
- Variegate darter (Etheostoma variatum)
- Waccamaw killifish (Fundulus waccamensis)
- Warpaint shiner (Luxilus coccogenis)
- Western mosquitofish (Gambusia affinis)
- Westslope cutthroat trout (Oncorhynchus clarkii lewisi)
- White Sands pupfish (Cyprinodon tularosa) [rare]
- White crappie (Pomoxis annularis)
- White sucker (Catostomus commersonii)
- Widemouth blindcat (Satan eurystomus)
- Wood River sculpin (Cottus leiopomus)
- Yaqui chub (Gila purpurea)
- Yaqui sucker (Catostomus bernardini)
- Yazoo shiner (Notropis rafinesquei)
- Yellow bullhead (Ameiurus natalis)
- Yellowcheek darter (Etheostoma moorei) [rare]
- Yellowfin cutthroat trout (Oncorhynchus clarkii macdonaldi)
- Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri)
Can I have river fish in a fishbowl?
Freshwater aquariums are very popular in many countries. They are not as difficult to maintain as saline aquariums and the price of fish is usually lower.
Most of the fish we find in the market have been bred in captivity (or so they should be) and are accustomed to the conditions of captivity. However, catching freshwater fish and putting them in an aquarium, in addition to being illegal with most species, is pointless and destructive. The probability of survival and adaptation to the new environment is in most cases nil.
Which fish go up rivers to spawn?
There are fish that spend most of their lives in the seas and oceans but, when they feel the need to reproduce, they return to the rivers where they were born. There, in most cases, they reproduce and die, leaving a large and new generation. When the offspring reaches the juvenile stage, they return to the sea. Many people think salmon are a type of freshwater fish due to this tendency to swim up freshwater rivers. However, the Atlantic salmon (salmo salar) is a marine fish, as the name attests.
These fish are known as anadromous. Some examples are salmon and sturgeon. On the other hand, there are fish that do just the opposite. They spend their entire lives in the rivers and only go to the sea to reproduce. They are catadromous fish. A good example is of this latter category is the eel.
If you want to read similar articles to Types of Freshwater Fish, we recommend you visit our Facts about the animal kingdom category.