Fish stores in California?

[Oilers]

I am taking my family for a trip down there for a few days. I am wondering if there are fish stores that you would recommend that I should visit. Also, what are the rules in term of bringing something back?
I'll be staying in the Anaheim area so that the kids can visit Mickey & Minnie. I'll also be going to the Knotts Berry Farm & Sea World. Anything else that I should pay a visit? I also love sushi. Any sushi restaurant to die for down there? Thanks all!