The ratios for lettuce generally decreased from the low to high biomass treatments because of the decreasing ratio of lettuce yield to fish yield. Ratios for fish did not differ significantly among treatment levels for any element. A general reduction of the solids ratio with treatment size was observed for most nutrients. This trend parallels an observed inverse relationship between treatment size and solids recovery. Mass recoveries of solids (weight of solids/weight of diet·100%) were 16.5% (151 g), 12.5% (377 g), 9.2% (902 g), and 8.8% (1804 g).