Two Terrapins which have been spotted in Clydebank are thought to be a pair 'illegally released' into the canal eight years ago.
The red-eared reptiles, sometimes referred to as water tortoises, were captured by a Clydebank Post reader this week as they rested on a log by the Forth and Clyde Canal.
The first reported presence of the creatures in the towns waterworks was in 2018 when a local photographer captured a 'family' of them.
Originating in the south of America and northern Mexico, they are classified as an invasive non-native species in the UK, warnings were issued that they can bite and carry salmonella bacteria.
Scottish Canals were informed of the issue when the Terrapins were first noticed and contacted NatureScot for advice.
They were told that although they have an illegal presence in the canal, they can be allowed to live their lives as long as they don't pose a threat to biodiversity.
Scottish Canals added that summers in the area are not warm enough to allow the creatures to breed.
A spokesperson for the public body stated: "Scottish Canals are aware of Red-eared terrapins on the Forth & Clyde Canal in the Clydebank area. They are classified as an invasive non-native species in the UK and have been released into the canal network illegally.
"Scottish Canals liaised with NatureScot in 2018 regarding the terrapins, following a newspaper article. The terrapins that have been spotted could well be the same ones found in 2018. They are long lived.
"NatureScot advised that Scottish Canals could leave them to live out their natural lives, unless they were threatening a particular biodiversity interest.
"The conditions on the Forth & Clyde Canal seem to suit the terrapins and they have survived in the canal environment for a number of years without posing a threat to our native species.
"It is unlikely that the terrapins would breed on the canal network as our summers are not hot enough for them to breed successfully."
