School Lane Fish Bar in School Lane first opened in 1976, and owners Luke and Helen Kyriacou said the business has gone from strength to strength.
Famous customers of the shop include broadcaster Chris Tarrant and former Coventry City manager John Sillett, who still regularly visits the shop.
Luke said: “There’s no secret to our success, we just put 100 per cent into what we do.
“We’ve got quite a lot of loyal customers, there’s many that still come after all this time. We have customers coming from Coventry, Warwick, Balsall Common, Leamington as well as Kenilworth.
“To keep the reputation of the business high for so long is difficult - other businesses might open and close in a year or two, but since 1976 we’ve gone from strength to strength.
“We have fresh fish delivered daily and we’ve used the same suppliers for 40 years - we have a great relationship with them.”
Helen explained the initial struggles when the shop first opened, and remained non-committal on the shop’s future when asked.
She said: “When we first bought it it was only a tiny little shop, so it was difficult to start with.
“Now we’ve been open for 40 years, we’ll just see how it goes from here.”
Luke and Helen also paid tribute to the many staff members who have worked for them during the business’s lifetime.
One such worker, Pat Barker, has been serving food at the shop for 28 years.
She said: “It’s not really like a business, it’s more like a big family here.
“I love the company you get here, and you often make good friends with the customers.”
As a way of thanking their customers, Luke and Helen will be offering 30 per cent off everything in the shop on Monday September 12, Tuesday September 13 and Wednesday September 14.