Technical Abstract: A series of grading trials were performed at the University of Arkansas at Pine Bluff and on commercial catfish ponds to determine if a new in-pond horizontal floating bar grader is more efficient and outperforms current live car grading techniques. Three replicate trials were conducted at UAPB with three fish size distributions (75:25, 50:50, 25:75 sub-harvestable to harvestable fish) during three different temperature ranges (> 26°C, 12.8-26°C, < 12.8°C). Commercial trials were replicated three times during each temperature range with the size distribution of fish in the pond at harvest time. Stress was measured by mean glucose and cortisol levels. Grading speed was significantly greater (P<0.05) with the UAPB/Heikes grader (105-219 kg/min) than the traditional live car (0.5-0.6 kg/min). The UAPB/Heikes grader significantly decreased the proportion of sub-harvestable fish during all trials. However, the traditional live car did not significantly grade fish during commercial trials nor in the 25:75 distributions during hot and cold trials. The UAPB/Heikes grader returned from 2-52 times more sub-harvestable fish by weight to the pond than the traditional live car grader. Glucose and cortisol levels in fish graded with the two grading technologies were not significantly different. The UAPB/Heikes grader sorted fish more accurately and consistently than the live car at all temperatures in both experimental and commercial trials. Additional research is needed to evaluate the economic feasibility of this new grading technology.