Populations of the Spanish toothcarp are estimated to have declined by at least 50 percent in the past ten years and, with numbers continuing to decrease, its threatened status shows no signs of improving (1). This population decline is due in part to competition with the mosquitofish (Gambusia holbrooki) (2); introduced by man to the region as a method of controlling mosquito numbers, this fish is one of the most invasive fish species worldwide (5). As a result, the Spanish toothcarp is now restricted to bodies of water where the mosquitofish is absent (1).
Habitat loss is the other major threat facing the Spanish toothcarp, as tourism and intensive agriculture over the last 30 years has led to the destruction and alteration of the toothcarp’s habitat (2). Pollutants, such as nitrate fertilisers that have been washed into streams and lakes from local golf courses, are also degrading this species’ habitat (2).