When his sister is taken, a rule-loving fiddler crab breaks out of his shell and dives claw first into a global climate crisis to save her.

Thanks for your reply. Bisque made me chuckle! All good points to consider.

A crab story, nice.

Bisque for thought 😉
Crabs migrating in and out of the water could answer how the protag-crab’s sister came up missing?
What if a climatologist took the sister crab to study?
Is he an Ordinary crab, like Emmet’s character from The Lego Movie?
We go from a close nit crab-commune to a global climate crisis – can the crab’s endangered habitat bring this closer to home?

This is your story, and I’m out of crap puns 😉 - keep going!

Thanks for your thoughts! Great stuff.

A like the idea of an animated family adventure involving a timely issue like the global climate crisis so you've got a great hook. I think a bit more detail could strengthen the logline. I'd clarify how or by who the sister crab gets taken and how the protagonist crab "breaks out of his shell" to save her. Something to help visualize the story more. Overall, I like what's here.