The zooplankton community of Lake Livingston was examined in terms of composition, abundance, distribution, and appropriateness as a food resource for paddlefish,Polyodon spathula. By comparing the range of interraker distances of paddlefish (0.06–0.08 mm) to size measurements of different zooplankton taxa, we determined that paddlefish do not consume small rotifers and copepod nauplii as efficiently as they do larger, copepods and cladocerans. All zooplankton taxa (rotifers, cladocerans, and copepods) were comprised of relatively small organisms, and community abundance and biomass were dominated by small rotifers and copepod nauplii most of the year. In fall and winter, however, the biomass was dominated by copepods. A bioenergetics model predicted the paddlefish biomass that could be supported in Lake Livingston at a density of 1.17 kg ha−1, with a range of 0.06 to 10.45 kg ha−1.