Birmingham residents were left confused after a canal was turned bright green.
Canal & River Trust West Midlands have advised people not to be alarmed after they dropped the dye into the Tame Valley Canal.
The canal charity said it was dye-testing in order to track down any leaks.
The dye is harmless to wildlife and will naturally disperse over the coming days, the charity added.
“If the canal is leaking at any spot, we will notice green dye not in the canal,” a spokesperson said.
“If we have a leak on the towpath for example the dye will make it easier to see,” they added.
The dye is harmless to wildlife, the charity said
(@CRTWestMidlands/Twitter)
The canal stretches eight and a half miles from the Walsall Canal to Salford Junction.
Socials media users have been quick to provide humorous explanations for the green hue.
One user joked the canal had been dyed green to mark St Patrick’s Day – three days after the Irish holiday.
Another said large amounts of mushy peas had been dumped in.
A notice on the Canal & River Trust website stated it was investigating the source of water in gardens near to Gorse Farm safety gate in Hamstead.
“There has been no obvious source of a leak discovered and monitoring has not determined conclusively the source of the water,” the update said.
“However, we have carried out repairs to one potential area and now need to test this under normal water pressure by refilling the canal.”
In a post on X, the canal charity said: “If you’re out on the Tame Valley Canal today don’t be alarmed by its green colour. We’re dye testing to check for leaks. And yes, it is safe to our wildlife and fish populations. The dye will naturally disperse over the next few days.”