The dog is being cared for in Birmingham
RSPCA officers are still searching for the owner of a dog - three days after it was found with its head wedged in a canal ladder.
Firefighters rescued the terrier-cross, who has been nicknamed Nelson, after it fell by a lock gate near Deykin Avenue, Birmingham, on Sunday.
The dog was found "shivering with extreme cold" and had scuffed its nails trying to get out, the RSPCA said.
Nelson was rescued after being spotted in the water by a cyclist.
The dog is currently being cared for at the RSPCA's animal centre in Weoley Castle, Birmingham.
The dog has been nicknamed Nelson by his rescuers
Tim Scott, an RSPCA inspector, said the dog had had a lucky escape.
"He was actually jammed in the bottom rung of the ladder leading out of the canal," he said.
"He obviously had been trying to get out himself because he's injured the bottom of his paws.
"If he'd stayed there any longer he could have been in trouble and could have got hypothermia or possibly even drowned - but he's actually all right."
Mr Scott added: "We don't know whether he fell in or whether there is anything more sinister to it."
The RSPCA said all dogs should be kept under control in public places and recommended that they were microchipped in case they got lost.
The dog has recovered well