Best simple fish dishes in East Bay/BART adjacent?

I have a quandary: I’m being visited by a relative with a staggering list of food no-nos. I want to take her out to dinner somewhere interesting (she lives in a not-terribly-exciting city for food), but wheat, rice, corn, dairy, meat, shellfish, mushrooms, winter squash, mushrooms, potatoes, sweet potatoes, and processed sugar are all out. I know.

She likes fish a lot. I’m currently leaning towards going to a Korean restaurant for tofu soup and a grilled mackerel dish, but would be open to other suggestions. Maybe Cantonese or Vietnamese places with simple fish preps? Anywhere between Richmond and Oakland is fine, bonus points for being somewhat BART-adjacent although we can Uber as well. Would prefer to keep it under $30 per entree or so.

Since you mention Cantonese, here’s a similar idea. Go to any of the Cantonese restaurants next to BART with seafood tanks, like Peony or Bay Fung Tong. Get a good looking 1.5 pound live fish that is <$30/lb and have it steamed. Then get a tofu dish or something your relative is interested in. Not sure what to do with the carb though.

Yeah, Bay Fung Tong occurred to me, but I forgot they had tanks. Good idea, thanks.

You may just want to call the restaurants on that day before you go to make sure they have some fishes for you to choose from if the whole meal hinges on the fish.