The fartet or Aphanius iberus is an endemic fish of the Iberian Peninsula of only five centimeters in length, although the females are usually a little larger. Males and females also differ in color: while men are more showy and have silvery scales, female fartets sport a darker and more irregular color.
It is a species distributed only along the Mediterranean coast. It can live in both fresh and salt water, in ponds, irrigation canals, coastal lagoons, salt flats or river mouths, demonstrating great adaptability.

Their main prey is insect larvae, although their diet varies throughout the year. Its diet is completed with vegetables, crustaceans and detritus, which is why it is considered an omnivorous animal. The fartet is declared an endangered species since its distribution has been significantly reduced in recent years, going from 28 to 16 known populations. One of the main causes of its disappearance is the degradation of its environment due to the products that are massively used in agriculture in the areas where it lives. In addition, the fartet is also affected by the introduction of new exotic and invasive species of fish such as the fundulum and the gambusia, as well as by the overexploitation of aquifers.

This species is important for its effectiveness in controlling invertebrates (mainly mosquitoes) so its disappearance would have significant consequences on the ecosystem. With the intention of halting its decline, the Biodiversity Foundation of the Ministry of Agriculture, Food and the Environment and the University of Balmes Foundation are collaborating in the SOS-Fartet project, an initiative that aims to determine the current state of conservation of the species and its habitat in the natural parks of Girona and, subsequently, if necessary, update and improve the management plans for these areas.