3.2 | Intestinal tissue morphology
The VH, VW and MT differed significantly among the four feeding habits of the fish species (Figure 1; p < .05). The intestinal microvilli of carnivorous fish had many branches and complex structures. The order of microvilli complexity was carnivorous > herbivorous > filter-feeder > omnivorous. Herbivorous fish had significantly higher VH and VHI than filter-feeder, carnivorous and omnivorous fish species (p < .05). Similarly, carnivorous fish had significantly higher VH and VHI than filter-feeder and omnivorous fish species (p < .05). Likewise, filter-feeder fish had significantly higher VH and VHI than omnivorous fish species (p < .05). On the contrary, carnivorous fish had significantly higher VW, MT, VWI and MTI than herbivorous, filter-feeder and omnivorous fish species (p < .05). Similarly, herbivorous fish had significantly higher VW, MT, VWI and MTI than filter-feeder and omnivorous fish species (p < .05). Likewise, omnivorous fish had significantly higher MT, VWI and MTI than filter-feeder fish species (p < .05). However, filter-feeder and omnivorous fish species had no significant difference in VW (p > .05).