I have bemoaned the lack of a fishmonger in our town. Our only fish counters are Tesco and Waitrose. The former has some reasonable offers but it seems to be based on whatever the delivery lorry is offloading and you cannot order things. Waitrose is a bit more customer friendly in the fish department.
Most people in this country focus on cod, haddock or salmon all of which have some problems of supply. You also end up paying £7-13.00/kg or even more. So in a similar price category to prime cuts of beef.
Some fish are under-appreciated and are more economic. I have always thought mackerel was under-rated though my Dad refuses to eat it as a "scavenger fish". However mackerel is reasonably priced.
A month ago in the Netherlands I really enjoyed the smoked sprats I was offered. Sprats are a smaller cousin of the herring. They are in season now and I was pleasantly surprised to see that the Tesco fish counter sold them at just £2.89/kg. We will have a cost-effective lunch tomorrow.
tc_how
goans love Mackerel and eat all seafood has to offer.. I have tried mackerel and It was lovely ,fresh and delicate 
Well, I consider myself lucky as we live in a state along the coast, so always comes with choices of fish whenever goes to the wet market. Unless the sea got too rough or during the festive celebration, then we will be lack of supply.
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I love sprats too, but it's a bit fussy of cleaning them, as they're smaller size, and you will buy in big quantity. But when come to good food, everything is reasonable