Spanish continental waters are home to about 40 species of fish belonging to 13 families. The vast majority are indigenous, and others have been introduced more or less recently (carp, crucian carp, mosquito fish, pike, largemouth bass, brook trout, rainbow trout). Not all are exclusive of inland waters, as in some life cycle takes place partially in seawater (sturgeon, salmon, eel) or brackish (thorny). The families represented are included in two major groups: bony fishes (teleosts and condrósteos), and jawless fish (cyclostomes).

Cyclostomes

• Petromizontidae: sea lamprey

Fish bone
Condrósteos

• Acipenseridae: sturgeons

Teleosts

• Anguillidae: eel
• Blenidae: monk
• Centrarchidae: largemouth bass
• Cyprinidae: small head catfish, catfish common mountain catfish, roach, Nase, chub, chub Sierra Morena, Calandrino, carp, crucian carp red comiza, culirroyo, roach, jarabugo, madrilla, teal, Minnow, tench
• Ciprinodontidae: fartet, samaruch (samarugo)
• Cobitidae: loach, lamprehucha, otter
• Cottidae: Cavilat
• Esocidae: pike
• Gasterostidae: thorny
• Poeciliidae: Gambusia
• Salmonidae: salmon, brook trout, rainbow trout, brown trout

Endangered Species

In the Spanish Catalogue of Species Amena collected a total of 11 taxa that are classified as follows:

• Fartet (Aphanius iberus): is found mainly in Catalonia and Andalusia Valencina Community. It can be found in ponds, lakes, coastlines, estuaries and lower reaches of the river channels. It feeds mainly on aquatic insects. The main threats are trade, alien species and the fragmentation of their populations.
• Samaruc (Valencia hispanica): extends from the Ebro Delta to the marshes of Catalonia and Valencia. The brink of extinction. Has a preference for coastal freshwater ditches and irrigation canals with abundant vegetation.
• Esturión (Acipenser sturio): located between the Guadiana and the Guadalquivir and the sea along the coast peninsula. His life is spent mostly at sea rivers flow back though medium and large to reproduce.
• Lamprea marina (Petromyzon marinus): located on the Cantabrian coast, estuary of the Guadalquivir, Ebro Delta, etc.. Is virtually extinct in southern Spain and a sharp decline in their populations in the North. It is an anadromous migratory species entering rivers with sandy bottoms to spawn.
• Jarabugo (Anaecypris hispanica): found in the Guadiana basin. It is a rare species and very fragmented. One of the best populations in the NP Cabañeros. Have a preference for rivers and slow-flowing streams with abundant submerged vegetation and stony bottoms.