Tesco is embarking on a complete packaging overhaul for its own-label pre-packed chilled fish in a bid to attract more affluent shoppers into the category.

The project referred to internally by Tesco as 'Revolutionise Fish' will see the majority of Tesco's wet fish lines repackaged from plastic trays with film on top into black Darfresh packaging, which sits tightly around the fish portions.

The revamp was a sign that Tesco recognised it needed to appeal more to fine-food shoppers and to put quality at the forefront of its message, said Simon Smith, sales and marketing director at Seachill, which worked with Tesco on the new packaging. "It looks very foodie, it makes the fish the hero, it really brings out the quality and freshness. You can almost touch the fish without actually touching it."

Black packaging was chosen after it emerged as consumers' favourite colour during market research. "Fish is either white or yellow or pink and it just looks fantastic with a black background," said Smith.

The new Darfresh packs are being rolled out nationwide across all 1,800 stores following a trial - which kicked off in April - in Tesco's Harlow depot which supplies about 150 stores that resulted in a sales uplift of between 5% and 12%.

"The uplifts experienced in the trial gave us great confidence in the initial research findings it was clear that the appeal of the fixture was vastly improved," said Scott Pearson, Tesco buying manager for fish.

Tesco Value fish will stay in clear packaging to distinguish higher-value tiers, and larger salmon lines will be re-packaged in black trays, as Darfresh packs would not stack well in the chiller cabinets in which they are sold.

Sales of pre-packed wet fish at Tesco were up 1.8% by value to £16.7m in the 52 weeks to 3 October and 7.8% in the 12 weeks to that date.

Marks & Spencer is thought to be the only other major retailer in the UK that uses Darfresh packaging for fish, although it uses clear rather than black packaging.