Around 12,500 miles of England's rivers have been opened up in the past four years to allow fish to migrate more easily, the Environment Agency said.
Fish passes have been installed, or weirs removed, to overcome almost 200 obstructions on rivers hindering fish as they migrate to reproduce, feed and complete their life-cycles.
The work aims to help coarse fish which spend their lives in rivers, as well as species which migrate between rivers and the sea such as salmon, sea trout and eels, the last of which make a 3,000-mile journey across the Atlantic and back to English rivers.
The steps to remove or get round weirs create "fish highways" from the sea up to the upper reaches of rivers, the agency said, though some of the weirs have to be left in place to prevent flooding, damage to buildings or to maintain heritage features.
Recent efforts to open up the rivers include removing two weirs on the River Don in Sheffield and a weir on the River Aire in Leeds, with both rivers now returning to a natural combination of shallow fast sections and deeper pools which benefit grayling and brown trout.
On the River Tyne in Northumberland, partners including the Environment Agency worked to build the Hexham fish pass to open up miles of spawning and juvenile habitat.
Sarah Chare, head of fisheries at the Environment Agency, said: ""After considerable investment, rivers in England are the healthiest for 20 years. This is down to more than a decade of hard work to improve the health of England's rivers.
"But there is more to do and opening up our rivers to help fish migrate is a crucial part of this. By working with partners we can play to different organisations' strengths, make our money go further and deliver more."