Variations in length, weight and length-weight relationships in the European minnow Phoxinus phoxinus (L.) due to f ia t ion andpreservation processesThe present study atternpts to clarify whether length pararneters, total weight and their interrelationships on fixated and preserved fish samples are useful elernents for fish biology research. Males European rninnow Phoxinus phoxinus (L.) were captured, rneasured, weighed and then stored in 5% formalin. Four months later they were again measured and weighed. The fish were washed and preserved for another four months in 70% ethanol, measured and weighed again. There was no significant difference in length, weight, length and length-weight relationships nor in condition factor after forrnalin storage. A significant difference in fresh and forrnalin sarnples versus forrnalin-ethanol sarnples in lengths, weight and lengths and standard length-weight relationships was observed but differences in Fulton Condition Factor were not significant. In this species, preserving specirnens in formalin for rnorphometric analysis may be valid. After formalin-ethanol storage sarnples are no longer valid other than for the condition factor.