Fig. 5.

Position of stained wood in the intestine of Panaque nigrolineatus at different time intervals following its consumption. The fishes were allowed to graze on the wood for 4 h (pulse), at which time the stained wood was taken away from the fish and replaced with non-stained wood so the fish could continue to feed. Four individual fishes were sacrificed and the position of stained wood in the gut observed at 4, 6, 8, and 18 h following commencement of feeding on the stained wood. a Graphical representation of the proximal-most position of stained wood in the fishes’ intestines at different time intervals. b Stained feces present in aquaria at the 4-h interval, indicating gut transit of less than 4 h. c Photographs of the fishes’ intestines at different time intervals showing the red-stained wood in their intestines. The arrows indicate the proximal-most position in the stained wood in the fishes’ guts at the time of death (scale bar = 150 mm). No stained wood remained in the intestine at 18-h post feeding (photo not shown) (color figure online)