I found this charming book 'Clarty Jim McCloud' by Tim Archbold at the Edinburgh International Book Festival.
Clarty Jim lives with his granny in a ramshackle house in the shadow of the ironworks. Every day his gran makes him horrible sandwiches for school, which he throws into the river, and a giant very hungry catfish gobbles them up.
One day Jim has to leave school and start working at the ironworks. As he no longer passes the river the catfish doesn't get his daily sandwich. So the hungry catfish swims upstream to search for food. A great story accompanied by funny and characterful line drawings.