Fish Sandwich for lunch?
First choice - a grilled fish sandwich in the BoCoCa (did I just say that?) area
Second choice - are the fried whiting places in Downtown Brooklyn open on Saturdays?
Third choice - chip shop
1st choice: cod sandwich at Brooklyn Fish Camp (yes, it's $12. It's big enough to split, and comes with fries. the condiments on the sandwich are perfect, and include cornichons)
2nd choice: catfish burger, well-done, at Bonnie's. Only open for lunch on the weekends
This list is 100% skewed by what I can walk to from home, but both sandwiches are very very tasty.
First Choice: The Seared Tuna Sandwich at Crave on Henry Street. Get it with the fries which are great. You can't go wrong this sandwich is excellent.
On Atlantic Avenue, the catfish po'boy at Waterfront Ale House is quite tasty and I also highly recommend the grilled salmon sandwich at Downtown Atlantic the coleslaw that they serve it with is positively addictive.
Thanks everyone for the suggestions. It looks like I have several more sandwiches to try.
We ended up at Dumont Burger that night where I had a perfect fried skate sandwich. Homemade tartar, not greasy, quality bun. Worth checking out if you're in Williamsburg.