With the present work, we intend to clarify the molecular mechanisms of response to anemia in a commercially relevant teleost fish, the European sea bass (Dicentrarchus labrax), by investigating the expression of several genes known to be involved in iron homeostasis and hematopoiesis, with a particular focus in understanding the roles of the different hepcidin genes. The gene discussed is HAMP; the disease is anemia (phenotype).