<p>Light trapping can be an effective tool for studying larval fishes but is not without its challenges. While the effect of different light lures on light-trap sampling efficacy has been well studied, the potential effect of within-trap predation on larval abundance has received little attention in the literature. To test whether exclusion of juvenile and adult fishes from quatrefoil light traps would improve larval collections, an exclusion mesh was applied to two different trap styles, one with larger and one with smaller openings, and combined with either a high-intensity, white light or a low-intensity, green light and tested against unmeshed controls. The interaction of these variables was often complex but, overall, larval catch was improved with gear combinations that reduced the size of fishes in the traps. The minimum size at which this effect occurred was linked to the size of the ontogenetic shift to piscivory of largemouth bass, the most abundant piscivorous species. The high-intensity, white-light traps collected smaller fishes and, combined with traps with smaller openings and exclusion mesh, the highest numbers of larvae. Large-opening traps with low-intensity, green light, and exclusion mesh collected the largest fishes and the lowest numbers of larvae. The exclusion mesh also improved retention of fishes in most trap combinations when traps were collected past sunrise. The negative effect of juvenile and adult fish presence on larval abundance in light-trap studies could have serious consequences when interpreting and applying results to management decisions and should be considered during study design and analysis.</p>