There was significant shrinkage in the body lengths of larvae of the myctophid fish Diaphus slender-type spp. for the first two weeks after they were preserved in 5% and 10% formalin, 70% and 90% ethyl alcohol, and 70% isopropyl alcohol solutions. The shrinkage was greatest in 70% isopropyl alcohol, followed by 90% ethyl alcohol, 70% ethyl alcohol, and the formalin solutions. No significant difference in shrinkage was observed between the 5% and 10% formalin solutions. Linear regressions described the relationships between body length before and after 140 days of preservation.