Strolling by Sun Kau Shing Market (1350 Stockton at Vallejo) I spotted them: stacks of boxes labeled Ca Ba Sa in Vietnamese and "Basa Fish Steaks in Claypot" in English. The price? $2.99 each or two for $5.00. Inside each box are two frozen basa (Vietnamese catfish) steaks (amounting to about 12 oz.) and a seasoning packet. These are packed inside AN ACTUAL CLAYPOT which itself is vacuum-wrapped in plastic, and the box has simple instructions for preparation, I haven't tried them yet, as the first one is defrosting in the fridge per instructions.
I can 't tell how much of a bargain as it is until I'd tried them, but the frozen steaks look wholesome enough, and there's nothing scary about the ingredients (Basa fish steak, onion, garlic, sugar, fish sauce, pepper). And what the hey, even if I the fish bombs, I'm left with two clay pots for $5.00).