Perhaps if they suggestedit had legs, they were suggesting a lungfish. They've got the closest things to fins in the fish world (along with the coelacanth), in being lobe-finned fishes. If it has no fins or legs, and is similar to a lungfish, than chances are it's a swampeel (not a true eel, I believe that there are 3 genera of them, the one that you are most likely to encounter in the UK is the asian swampeel, Monopterus albus).