Quatrafoil light traps are routinely used in the study of larval fish. They are inexpensive, easy to deploy, and are generally an effective means of capturing fish larvae in a wide range of aquatic environments. This study demonstrates that juvenile and adult small-bodied fish frequently encountered as by-catch in light traps can significantly reduce the abundance and diversity of fish larvae sampled via confined predation within the trap prior to clearing. To counter this problem we experimentally examined the effect of fitting a fine mesh to the outside of light traps to exclude adult small-bodied fish thus effectively reduce the predation effect within the trap. The experiment was carried out in the field during January 2007 in the Lindsay River, an anabranch of the lower River Murray in north-west Victoria. Results showed that traps fitted with mesh effectively excluded adult small bodied fish to result in a significant increase in the number of larvae sampled as compared to standard light traps. These results support the use of mesh on light traps to reduce confined predation and enhance sampling efficiency.