Ice fishing is no longer allowed on Echo Lake, there is a sign at the Main parking lot. I talked to the Denver Parks Dept. last year about it and they had no interest in discussing why they wouldn't allow ice fishing or any other activity on the ice. I pointed out that the city of Denver allows ice activities on other lakes like Antero but the response was that's another department and we have different rules then they do.
I would think the Parks Dept would try to open as much area as possible for recreational access but that doesn't seem to be the mission of the current administration.