It is only possible to fish from the daybreak till the twilight.
How to reach Dobbiaco/Toblach: https://www.drei-zinnen.info/en/dobbiaco/dobbiaco/contact-and-service/arrival-mobility.html
From Dobbiaco in southern direction. The lake is located on the left side after the viewpoint of the Three Peaks.
Parking places are available.
Also accessible by public transport. The timetables are available on www.sii.bz.it.