The study was carried out at Karantina Island located on the west side of Izmir Bay, Aegean Sea, Turkey. The fan mussel spats were cultured on the single long line system. Shell length and total weight of spats were measured monthly from December 2004 to April 2006. In total, 590 the fan mussels were sampled, 466 of which were obtained from collectors and others were collected by diving. Age-related length and weight growth factors of the fan mussel evaluated with four different model. The RSS values of all estimates were highly reliable; length and age values were significantly higher than weight. Von Bertalanffy's growth parameters showed that the fan mussel has a slowly growing species. The maximum estimated length size obtained with bivalves was 78.58 cm, growth performance index or phi-prime test (phi') was 3.33 for Izmir Bay. According to this study also Richards and the Logic model can be found in older ages (>7 years) to be more appropriate. However, von Bertalanffy was more suitable for the older of fan mussel. As the age increases, growth decreases and even rest are expected, but the fan mussel individuals may have age related weight gain.