Triaeris stenaspis Simon 1891 is a parthenogenetic goblin spider that has been introduced into greenhouses all over Europe. Here we investigated its trophic niche and predatory behavior. Potential prey in the greenhouses included predominantly springtails, aphids, and other spiders. Out of ten potential prey types offered in the laboratory, T. stenapsis captured only three types, the primary one being springtails. The spider rarely caught the other two types, termites and crickets, and completely rejected beetles, ants, aphids, thrips, flies, spiders and mites. Triaeris stenaspis did not build webs for prey capture, but instead used the grasp-and-hold tactic. Prey-capture efficiency decreased with springtail body size, the spider using more than three bites to capture large springtails. Large springtails defended themselves by saltation with the spiders still attached to their backs. Our study supports the hypothesis that T. stenaspis is a specialized predator of springtails, being effective in the capture of this type of prey.