Plants vs. Fish

ZOMBIE FISH!  Just kidding.  This is just a short post about something I noticed.  I don't really understand the reasons for it, but maybe you do.  So while a group of people with me were eating sushi (some of whom had never tried it before) they were discussing related topics.  One person stated that they were fine with sushi, but are more hesitant about eating potentially poisonous fish.  I completely understand that someone might not be gung ho about eating sushi made from poisonous fish.  What I don't get is that people have no issue eating things like a rhubarb pie, but are completely against sushi from poisonous fish.  Some fish are potentially poisonous, but when prepared properly they are safe for consumption.  This is the same with rhubarb.  Rhubarb is potentially poisonous but if prepared properly (i.e. without the leaves) most have no problem with eating it.  Both are poisonous living things that if correctly served are consumable.  So why does the poisonous fish seem more intimidating to eat?  Kinda weird, so for now I'll just stick to eating no sushi at all.