At the risk of sounding like I'm spouting off a cliche, rattlesnake tastes like chicken. Well... not
exactly like chicken. Imagine a chewy skinless chicken breast with a slightly tangy taste.
You're right about shark. Yum!
About the only type of fish that I have never been able to eat was catfish. I guess that goes back to when I was a kid and had a friend who used to go fishing for them near a "water treatment plant".

Just thinking about eating a fish that survives off of fecal matter turns my stomach!