Welcome to the Candy Crush Saga Community
Do you have a question or need help with your game? Ask the Community.
UFO's will come automatically once you start winning in row. I dont remember but i got it after 1000. As 1-1000 are simple and just tricky, Might be thats the reason. But it will get automatically activated. It depends as for every player its different scenario
Might be this may be helpful.
Late reply but it's your own fault, I'm afraid. You shouldn't have blindly trusted mod's advice. I, personally, misunderstood your question at first - thought you were asking about UFO rewards.
In-level booster tasks are always about using your boosters. This includes UFOs, as well as Party Boosters, Free Switch, Lollipop Hammer. Unlike striped candies for example - you can collect them without activating a pre-level booster. This said, fishes are also collectible, i.e. you don't need to use a pre-level booster to fulfil the task, provided they can be summoned in-level.
In addition, all but "new level" and "first try" tasks can be completed by repeating old levels. Obviously, booster tasks require you to have those in stock. Hope this helps someone else. 👍