Not of the Equidae Family

Relaxes pretty well at deep sea pressures
Relaxes pretty well with a huge snout, strange fin,
and hell of curly tail
Relaxes while being oblivious to this blog post and incapable of conceptualizing it, but still maintaining an air of coolness that is only capable in nature (What you see on Discovery)
Relaxes pretty well while being a pregnant male!

Syngnathidae is a family of fish which includes the seahorses, the pipefishes, and the weedy and leafy sea dragons. Fish of this family have the unique characteristic whereby females lay their eggs in a brood pouch on the male's chest, and the male then fertilizes and incubates the eggs. The name is derived from Greek, meaning "fused jaw" - syn meaning fused or together, and gnathus meaning jaws. This fused jaw trait is something the entire family has in common.

Syngnathidae @ Wikipedia