It's thought that the duck got caught up after coming across piles of litter by the Leeds Liverpool canal in Accrington.
RSPCA Animal welfare officers rescued the duck using a boat and specialist nets. A vet then treated the duck for cuts to its beak and gave it antibiotics.
The duck is now in the care of a private "boarding establishment" and is due to be re-released locally in the coming weeks.
RSPCA inspector Mandi Barr said:
It was really sad to see this duck struggling and just shows the devastating effect litter can have on wildlife.
Thankfully we were able to rescue him quickly, but, had we not been alerted to his plight, the outcome could have been much more tragic.
The danger all these things pose to wildlife is substantial, even proving fatal in some cases, and the risk can be prevented by people taking responsibility for their litter.
There are still far too many animals and birds suffering as a result of litter.
Every animal trapped or injured because someone couldn't be bothered to dispose of their rubbish properly is one more than it should be.
Hard to disagree with the last point.