The lake and its environs are still open to the public
A warning over potentially toxic blue-green algae bloom on a Snowdonia lake has been lifted.
Signs were put up at Llyn Padarn near Llanberis in Gwynedd last month warning lake users not to immerse themselves in the water or let animals drink there.
But Gwynedd council said tests shows that the algae blooms had now subsided and the lake was now safe to use.
Residents and visitors are advised that the naturally occurring algae could return and fresh warnings could follow.
The algae, anabaena spirioides, has a 50% chance of being toxic and occurs naturally in inland waters, estuaries and seas. It cannot be removed or treated and can become abundant in warm, shallow, undisturbed surface water that gets a lot of sunshine.
Barry Davies, Gwynedd council's Maritime and Country Parks Officer, said: "We had no option but to restrict use of the lake earlier this month to protect public health."
Two consecutive samples, taken at least one week apart by Environment Agency Wales, have shown the algae blooms had subsided.
"Confirmation from Environment Agency Wales that the blue-green algae has subsided is excellent news for users of the lake and for local businesses.
"Despite this good news there is a note of caution," said Mr Davies.
He said the algae could return at at any time and the systems were in place to warn the public.
Mr Davies urged the public to look for warning signs which will be put up along the lake's shore and access points if the problem does reoccur.
Dylan Williams, the Environment Agency Wales team leader for Gwynedd, added: "We sample the water quality in Llyn Padarn on a regular basis.
"We are also undertaking further work to help find the cause of the blue green algae, which is part of a wider monitoring programme."