First things first: follow your nose. If your fish smells fishy, that isn’t a good thing since a fish that leaves a pungent smell is essentially either not fresh or has been contaminated by toxins. At the market though, fish sellers are always looking for an unassuming customer to sell their stale fish to. We meet Ali Raza Abidi, the owner of Karachi’s famous restaurant Biryani of the Seas, to discover his secrets of buying fish that is fresh.

“The best way to assess a whole fish is to hold it from its tail and check its body shape. If the body is bending in any direction in a pronounced way, the meat has gone to waste. Fresh fish will always be erect — this signifies that the muscles and tissues are still working.

Check the eyes; if the eyes are sunken inwards, the fish is useless. Fresh fish’s eyes should be bright, clear and bulging.

Then of course there are the gills: fresh fish will have reddish or a maroon shade of gills; stale fish will have brownish gills. Smell a fish through its gills too — if the smell is of blood, the fish is fresh. If it stinks of rotten meat or ammonia, the fish is useless.

One last indicator that many don’t know about is checking a fish through its anus: a closed anus signifies good, fresh fish, while a large open hole means that the fish has gone stale.

Just like fish, prawns need to be held from their head — what you are checking for is whether the prawn hangs. If it remains erect, it is fresh. Also check the tail: as prawns go old, black spots start emerging. If there are too many black spots, it is better not to buy that prawn. And if there is any kind of pungent smell, definitely stay away from that prawn.

For squids, check the colour: if the skin is whitish, the squid is absolutely fresh. If the skin is pinkish, the squid is fresh enough but needs to be cooked and consumed immediately. If the skin is reddish, the squid is edible but it won’t taste like fresh squid should.

The writer tweets @ASYusuf

Published in Dawn, Sunday Magazine, November 2nd, 2014