A characteristic feature of fish is the wide physiological range of blood parameters and also the large individual variations. The aim of this study was to compare the haematological profile, glucose and lactate levels of four teleost fish species (Gobius niger, Mugil cephalus, Sparus aurata, Dicentrarchus labrax) and to establish the similarities and differences between these species which are widely present in the Tyrrhenian Sea. To this end, glucose, lactate and complete haematological profiles were determined for 25 fish from each species. Statistical analysis confirmed statistical differences in blood parameters among the four species. Our findings show a lower level of glucose and higher levels of lactate, red blood cells and haemoglobin in M. cephalus with respect to the other species. White blood cell and thrombocyte counts have the same trend and result higher in S. aurata. The differences found in this study can be attributed to the feeding behaviour, life style and adaptation of the different fish species to the habitat in which they dwell.