Name of children's animated movie? (green grasshopper brooch/underwater)?

I really don't remember much about it but this is what I can remember:

It came out before 2005.

It's not Ariel, Atlantis or Pinocchio. I'm really pretty sure it's not made by Disney or Pixar.

It might have came on a videotape that had other short children's films on it as well.

It was a western style 2D animation. Quite a lot of squash and stretch if I remember rightly (like Fleischer Studios or Cuphead)

The main two humans were a boy and a girl.

There was a emerald cricket/grasshopper brooch that came alive at one point and the story heavily revolved around it. They lose the brooch at one point.

There was an underwater city or castle. The girl might have nearly drowned, did the brooch give them air underwater?

Thank you all for any answers. I've been looking for the name of this for years now. :)