Level 251 is the sixth level in Delicious Drifts and the 109th jelly level. To pass this level, you must clear 29 double jelly squares in 30 moves or fewer.
When you complete the level, Sugar Crush is activated and will score you additional points.
There are many liquorice locks, so it might be a good idea to break them using special candies. Try to create vertical striped candies if possible on top of the liquorice locks to remove an entire column of liquorice locks from the beginning. On mobile versions, you can exit and reenter a level until this happens to get a head start.
Try to conserve the jelly fish for later, or combine a special candy with a fish after most of the liquorice locks have been cleared to trigger combination effects.