The variety of river fish that exist, despite not being as numerous as that of marine fish, is equally overwhelming. These animals require their environment to have specific characteristics in order to survive, especially with reference to salinity. That is why in this article on our site we will talk about river fish, we will know how they differ from sea fish and we will see dozens of examples.
Difference between river fish and sea fish
To talk about the difference between river fish and sea fish we must first define the term homeostasis, since here lies the decisive difference. Homeostasis is the process by which a living organism keeps its vital processes stable despite the changes that occur in its environment.
The river fish have greater facility in this aspect, since their external environment is more similar to the internal one, since the salinity of the water is not high. Thus, the water passes through its gills and out through the operculum without much resistance. In addition, they have very developed kidneys to properly filter the water.
On the other hand, the sea fish have an added difficulty, and that is that their environment is excessively saline. Then, by breathing through their gills, a large amount of body water is expelled. For this reason, sea fish drink a lot of water, whose kidneys process to expel excess s altand maintain homeostasis.
Dangerous river fish
It may seem that river fish are less dangerous than those that inhabit the oceans and seas. But highly dangerous creatures lurk in the rivers, lakes, and wetlands in certain parts of the world, many of which have killed people in the region:
Piranhas (Subfamily Serrasalminae)
Piranhas are freshwater fish that inhabit the rivers of South America, such as the Amazon River and its tributaries. A single piranha can perhaps do little damage, although its jaws are very strong A large group of piranhas can kill an animal trapped in the river in just a few minutes.
The electric eel (Electrophorus electricus)
Despite its name, this fish is not really an eel It lives in South America, in the Amazon and Orinoco rivers. It prefers muddy areas, such as mudflats. It doesn't matter if the water is poorly oxygenated because this fish breathes air. Its danger lies in the fact that, in order to hunt, defend itself and communicate, it produces strong electric shocks sustained for more than a minute thanks to some organs that they have in their heads and that they can even kill a person.
The alligator gar (Atractosteus spatula)
This fish is distributed in the eastern part of Central America. It can reach more than 3 meters in length and exceed 200 kilograms in weight. In its upper jaw it has two rows of very sharp teeth.
+90 river fish in Spain
In Spain, continental fishing has been a way of obtaining food resources for centuries. Its rivers, lakes, wetlands and lagoons have always been rich in a wide variety of edible fish. However, in recent decades exotic species have been introduced that have damaged our fish fauna.
Below we present two lists, one with the fish of the Iberian Peninsula and another with the introduced species:
List of fishes of the Iberian Peninsula
- River lamprey (Lampetra fluviatilis)
- Brook lamprey (Lampetra planeri)
- Costa de Prata lamprey (Lampetra alvariensis)
- Nabao Lamprey (Lampetra auremensis)
- Sado Lamprey (Lampetra lusitanica)
- Marine lamprey (Petromyzon marinus)
- Sturgeon (Acipenser sturio)
- Sábalo (Alosa alosa)
- Saboga (Alosa fallax)
- Eel (Anguilla anguilla)
- Salmon (Salmo salar)
- Common trout (Salmo trutta)
- Jarabugo (Anaecypris hispanica)
- Common barbel (Luciobarbus bocagei)
- Comizo barbel (Luciobarbus comizo)
- Graells barbel (Luciobarbus graellsii)
- Mediterranean barbel (Luciobarbus guiraonis)
- Red-tailed Barbel (Barbus haasi)
- Mountain barbel (Barbus meridionalis)
- Short-headed barbel (Luciobarbus microcephalus)
- Gypsy Barbel (Luciobarbus sclateri)
- Bermejuela (Achondrostoma arcasii)
- Ruivaco do Oeste (Achondrostoma occidentale)
- Ruivaco (Achondrostoma oligolepis)
- Sarda (Achondrostoma salmantinum)
- Loina(Parachondrostoma arrigonis)
- Burrow (Parachondrostoma turiense)
- Madrilla (Parachondrostoma miegii)
- Grabber (Iberochondrostoma lemmingii)
- Mira pardelha (Iberochondrostoma almacai)
- Portuguese Gray Partridge (Iberochondrostoma lusitanicum)
- Oretana Gray Partridge (Iberochondrostoma oretanum)
- Yew Arched Mouth Bogue (Iberochondrostoma olisiponensis)
- Douro Boga (Pseudochondrostoma duriense)
- Tajo Bogue (Pseudochondrostoma polylepis)
- Bogue del (Guadiana Pseudochondrostoma willkommii)
- Gobio (Gobio lozanoi)
- minnow (Phoxinus bigerri)
- Calandino (Iberocypris alburnoides)
- Bogardilla (Iberocypris Palaciosi)
- Bordallo (Squalius carolitertii)
- Arade Bordallo (Squalius aradensis)
- Catfish (Squalius laietanus)
- Malagueño chub (Squalius malacitanus)
- Cacho (Squalius pyrenaicus)
- Torgal Horn (Squalius torgalensis)
- Levantine chub (Squalius valentinus)
- Cacho del Gallo (Squalius castellanus)
- Tench (Tinca tinca)
- Lamprehuela (Cobitis calderoni)
- Colmilleja (Cobitis malaria)
- Alago's Fang (Cobitis vettonica)
- River Otter (Barbatula quignardi)
- Atlantic Tartet (Aphanius baeticus)
- Fartet (Aphanius iberus)
- Samaruc (Hispanic Valencia)
- Pejerrey (Atherina boyeri)
- Stickle (Gasterosteus aculeatus)
- Cavilat (Cottus hispaniolensis)
- Burtaina (Cottus aturi)
- Friar (Salaria fluviatilis)
- River needle (Syngnathus abaster)
List of introduced fish in the Iberian Peninsula
- Pacific salmon (Oncorhynchus kisutch)
- Rainbow trout (Oncorhynchus mykiss)
- Charr (Salvelinus fontinalis)
- Alpine charr (Salvelinus umbla)
- Pierke (Esox lucius)
- White bream (Blicca bjoerkna)
- Common bream (Abramis brama)
- Bleak (Alburnus alburnus)
- Redfish (Carassius auratus)
- Prussian carp (Carassius gibelio)
- Carp (Cyprinus carpio)
- Languedoc goby (Gobio occitaniae)
- Rutile (Rutilus rutilus)
- Gardí (Scardinius erythrophthalmus)
- Pseudorasbora (Pseudorasbora parva)
- Dojo (Misgurnus anguillicaudatus)
- Central European Wolf (Barbatula barbatula)
- Black catfish (Ameiurus melas)
- Spotted catfish (Ictalurus punctatus)
- Catfish (Silurus glanis)
- Fundulus (Fundulus heteroclitus)
- Gambusia (Gambusia holbrooki)
- Guppy (Poecilia reticulata)
- Little Pig (Australoheros facetus)
- Sunfish (Lepomis gibbosus)
- Smallmouth Bass (Micropterus salmoides)
- River perch (Perca fluviatilis)
- Pickle perch (Sander lucioperca)
Can I have river fish in a fish tank?
Freshwater aquariums are very popular with people in many countries. They are not as difficult to maintain as s alt aquariums and the price of the fish is usually less.
Most of the fish we find on the market have been bred in captivity (or should be) and are used to captive conditions. However, catching river fish and putting them in an aquarium, as well as being illegal with most species makes no sense, since the probability of survival and adaptation to the new environment is in most cases zero.
What are the fish that 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, return to the rivers where they were born There, in most cases, they reproduce and die, leaving a large new generation that, when it reaches the juvenile stage, returns to the sea.
These fish are known as anadromous Some examples are salmon and sturgeonOn 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 the fish catadromous A good example is the eels
