P. nigrolineatus (L-190) were imported from South America by the fish wholesaler Aquascapesonline (Belleville, NJ). They were randomly assigned to individual, filtered, and aerated tanks kept at 29 ± 1 °C. Fish (40 mm, standard length) were fed a mixed diet of hearts of palm (Euterpe precatoria), algae pellets (Hikari Tropical Sinking Algae Wafers, Hayward, CA), and date palm wood (Phoenix dactylifera) during an acclimation period of three weeks under conditions specified by IACUC 071509JW-01. For the duration of the experiment, the fish on a mixed diet were provided with palm hearts and algae every second day while wood was constantly available. Wood was thoroughly soaked in water and autoclaved three times prior to being provided to the fish. Fish were then converted to a palm wood-only diet or a mixed diet of palm hearts and palm wood. This feeding regimen was maintained for three weeks prior to termination.