Board Thread:Dragon City Questions and Answers/@comment-99.249.175.235-20130515225600/@comment-14284922-20130822010507

Absolutely.

I usually recommend Terra, because it usually results in the lowest times for most dragons and you can get additional exclusive dragons since Terra is often a common element in exclusive dragons. (Sky, Angry, Lava, Poo, Great White, Diamond, Bat, Deep Forest, Plankton).

But if you aim is Plankton, Legendary + Sea is perfectly valid.