The calandino (Iberocypris alburnoides) is a small freshwater fish with a slender, elongated body and relatively small fins. Its head is small, with an upturned mouth and relatively large eyes (2) (3) (4). Although it may grow up to 25 centimetres in length, the calandino more commonly reaches around 13 to 15 centimetres (2) (3).
The body of the calandino is mainly light grey (3), with a dark line along the side from the snout to the base of the tail (2). The dorsal fin is located relatively far back on the body, behind the pelvic fins (4).
This species has a complicated taxonomy, and has been assigned to several different genera by different scientists (1) (5) (6) (7). The calandino is unusual in having a hybrid origin, probably originating from a cross between two unrelated species. Its maternal ancestor is believed to be the southern Iberian chub (Squalius pyrenaicus), and the paternal ancestor may have been a species that is now extinct, but that was closely related to the jarabugo (Anaecypris hispanica) (6) (8) (9).
The calandino also has complex genetics, existing in two main forms: hybrid males and females which have two, three or sometimes four sets of chromosomes (diploid, triploid or tetraploid); and non-hybrid, diploid males (4) (6) (7) (9). These forms differ slightly in aspects of their morphology (6). Most populations of the calandino are dominated by triploid females (3) (4) (7).
- Also known as
- Iberian roach, Iberian-roach.
- Leuciscus alburnoides, Rutilus alburnoides, Squalius alburnoides, Tropidophoxinellus alburnoides.
- Length: up to 25 cm (2)
The calandino feeds on a variety of aquatic insects, insect larvae and other invertebrates, as well as some plant material (2) (3) (4) (10). Like other members of the Cyprinidae family, this species does not have teeth, instead processing food using modified bones in the throat, known as ‘pharyngeal teeth’ (11). The diet of the calandino may vary seasonally (10), and the different genetic forms also show slightly different foraging behaviour and food preferences (4) (10).
The breeding season of the calandino usually runs from March to July (2) (4) (12) (13). The female calandino may produce at least two batches of eggs a year (12), and each batch can contain around 150 to 1,300 eggs, depending on the size of the female (4). The eggs are usually released over gravel bottoms (2) (4). Both the male and female calandino reach maturity in the second year of life, and the lifespan of this species varies from about four to six years (4) (12) (13).
The reproductive system of the calandino is complex. The females of this species may mate with males of the southern Iberian chub (S. pyrenaicus), the northern Iberian chub (Squalius carolitertii) or the Arade chub (Squalius aradensis), forming hybrid offspring. The calandino also uses a process known as ‘hybridogenesis’, in which the female produces eggs from which the paternal genome (the genes inherited from the female’s father) are eliminated (3) (6) (7) (9).
The calandino is endemic to the southern Iberian Peninsula, in Spain and Portugal (1) (3) (8). It has been recorded in the Douro, Tagus, Sado, Guadiana, Odiel, Guadalquivir and Quarteira river basins (2) (3) (5) (8).
This freshwater species usually inhabits relatively shallow rivers and streams with abundant emergent vegetation (1) (3) (4). It has also been found in reservoirs (8).
The different genetic forms of the calandino use slightly different habitats. Diploid males prefer shallow areas with warmer water and a mud or sand substrate, while triploid females are more often found in areas with stronger currents and more vegetation cover (4) (8).
The calandino is classified as Vulnerable (VU) on the IUCN Red List (1).
Although the calandino is generally quite abundant, its population is expected to decline over the next ten years due to habitat loss and the impact of non-native fish species. The habitat of this small fish is under threat from dam construction, pollution, the over-extraction of water, and the extraction of aggregates (crushed rock and gravel), which destroys the calandino’s spawning areas (1) (2) (3) (4) (8). It is also under threat from droughts, which may become more frequent and severe with the effects of climate change (1).
The calandino is listed as ‘Not threatened’ on the Spanish Red Book (3) and as ‘Vulnerable’ on the Portuguese Red Book (8). This species is also covered by national and international conservation legislation (8), including the EU Habitats Directive (14) and Bern Convention (15).
No specific conservation measures are currently targeted at the calandino (3). However, recommended actions for this species include minimising the impacts of dams and aggregate extraction, controlling introduced species, restoring degraded habitat and improving water quality (3) (4) (8).
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- Term applied to a cell nucleus that contains two sets of chromosomes (threads of DNA protein), or to an organism that has two sets of chromosomes in its cells.
- Dorsal fin
- The unpaired fin found on the back of the body of fish, or the raised structure on the back of most cetaceans (whales, dolphins and porpoises).
- Aquatic plants whose stems and leaves extend beyond the water’s surface.
- A species or taxonomic group that is only found in one particular country or geographic area.
- (plural genera); a category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.
- The offspring produced by parents of two different species or subspecies.
- Animals with no backbone, such as insects, crustaceans, worms, molluscs, spiders, cnidarians (jellyfish, corals, sea anemones) and echinoderms.
- Stage in an animal’s lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
- The visible or measurable characteristics of an organism.
- Pelvic fins
- In fish, the pair of fins found on the underside of the body.
- The production or depositing of large quantities of eggs in water.
- The science of classifying organisms, grouping together animals which share common features and are thought to have a common ancestor.
- Term applied to a cell nucleus that contains four sets of chromosomes (threads of DNA protein), or to an organism that has four sets of chromosomes in its cells.
- Term applied to a cell nucleus that contains three sets of chromosomes (threads of DNA protein), or to an organism that has three sets of chromosomes in its cells.
IUCN Red List (May, 2011)
FishBase - Tropidophoxinellus alburnoides (May, 2011)
Doadrio, I. (2001) Atlas y Libro Rojo de los Peces Continentales de España. Dirección General de Conservación de la Naturaleza, Museo Nacional de Ciencias Naturales, Madrid. Available at:
Carta Piscícola Nacional - Squalius alburnoides (May, 2011)
Leunda, P.M., Elvira, B., Ribeiro, F., Miranda, R., Oscoz, J., Alves, M.J. and Collares-Pereira, M.J. (2009) International standardization of common names for Iberian endemic freshwater fishes. Limnetica, 28(2): 189-202.
Collares-Pereira, M.J. and Coelho, M.M. (2010) Reconfirming the hybrid origin and generic status of the Iberian cyprinid complex Squalius alburnoides. Journal of Fish Biology, 76(3): 707-715.
Collares-Pereira, M.J., Alves, M.J. and Coelho, M.M. (1999) Reassessment of the generic position of the Iberian cyprinid alburnoides complex: its return to the genus Leuciscus. Journal of Fish Biology, 54: 465-468.
Cabral, M.J., Almeida, J., Almeida, P.R., Dellinger, T., Ferrand de Almeida, N., Oliveira, M.E., Palmeirim, J.M., Queiroz, A.L., Rogado, L. and Santos-Reis, M. (2005) Livro Vermelho dos Vertebrados de Portugal. Instituto de Conservação da Naturaleza e da Biodiversidade, Lisbon. Available at:
Crespo-López, M.E., Duarte, T., Dowling, T. and Coelho, M.M. (2006) Modes of reproduction of the hybridogenetic fish Squalius alburnoides in the Tejo and Guadiana rivers: An approach with microsatellites. Zoology, 109: 277-286.
Gomes-Ferreira, A., Ribeiro, F. and Moreira da Costa, L., Cowx, I.G. and Collares-Pereira, M.J. (2005) Variability in diet and foraging behaviour between sexes and ploidy forms of the hybridogenetic Squalius alburnoides complex (Cyprinidae) in the Guadiana River basin, Portugal. Journal of Fish Biology, 66(2): 454-467.
Campbell, A. and Dawes, J. (2004) Encyclopedia of Underwater Life. Oxford University Press, Oxford.
Fernández-Delgado, C. and Herrera, M. (1994) Population structure, growth and reproduction of Tropidophoxinellus alburnoides (Steindachner 1866) in an intermittent stream of the Guadalquivir River basin (southern Spain). Archiv für Hydrobiologie, 130(3): 359-369.
Ribeiro, F. Cowx, I.G., Tiago, P., Filipe, A.F., Moreira da Costa, L. and Collares-Pereira, M.J. (2003) Growth and reproductive traits of diploid and triploid forms of the Squalius alburnoides cyprinid complex in a tributary of the Guadiana River, Portugal. Archiv für Hydrobiologie, 156(4): 471-484.
EU Habitats Directive (May, 2011)
Council of Europe: Bern Convention (May, 2011)