Rotifers are the first live zooplankton fed to larval red drum when cultured in controlled conditions within tanks. An investigation was conducted to identify a rotifer level that sustains growth and survival without overfeeding or negatively affecting health. The liver and gut, widely accepted organs to assess effects of diet on the health of finfish, were assessed histologically to determine the effect of rotifer level on fish health. Red drum larvae were cultured in 520 L tanks from 2 to 28 dph with rotifers fed continuously during a 12-hour photoperiod to maintain targeted rotifer levels from 2 to 12 dph. Vacuolization of the liver cells (hepatocytes), and intestinal enterocyte and microvilli heights were measured with digital image analysis (DIA) as indicators of pathology. There was an interaction between rotifer level and age of larvae wherein hepatocyte vacuolization was higher at the higher rotifer levels during the rotifer feeding phase, but vacuolization increased to similar measurements at all rotifer levels after the rotifer feeding phase. Enterocyte and microvilli height tended to increase with age and with rotifer feeding level. Although there was no effect of rotifer level on digestive pathology after the rotifer feeding phase, we did not test for long- term effects. The data suggests that feeding rotifers at 0.5-1.5/mL continuously to red drum during the first several days after hatch may provide suitable food for normal growth and survival and minimize short-term digestive pathology.