A fish fry pan

Seems to me that you should take option B

"B. I also have a rectangular aluminum thing, half of a food box, and it is about 8 inches long by 5 inches wide by 1 inch deep. It weighs only 2.95 ounces plus a gripper."

It seems to be the right aspect ration. If you catch a bigger fish, you can always cut the fish into steaks.

Jon

Do you have any wide-ish pots?

If you have one, that plus some sort of light tongs (bamboo) might suffice. Utensils could make up for lack of shallowness.

"Do you have any wide-ish pots?"

Yes, but their depth makes them far heavier. That is not what I had in mind.

–B.G.–

I think you are better off carrying the small frying pan and cutting the fish into halves before cooking.

I'd say it depends on the trip. If you're doing a relatively lax trip in regards to mileage and rigor, you would regret not bringing option A and missing out on a top notch fry job. Totally worth the weight.

Or you could check out a local kmart or Wal-Mart to see if they have a smallish thin Teflon pan that you can take off the handle from, if you don't mind acquiring yet another pan.

Sushi?

I'd take the 12" pan even though you have to reposition it to even out the heat, because it sounds like you're cooking for two. I'd take a Walmart 7-8" handless non-stick cheapo if soloing. I don't like messing around cooking too many fish in a tiny pan.

Bring some pepper too.

I like instant potatoes with fish – I usually freezer bag cook, so I put the spuds in the cozy while I cook the fish.

Use one half of a modified "Omelet Pan" cut to desired depth for weight elimination.