Guarding a fountain

Except when sleeping...

A dark dog keeps barking guard                              
Over a fancy fountain,
Gaily giggling

He hears every footstep passing
Like an assault on/or
Justifying his existence

Woof! woof! woof!
Gurgle, gurgle, gurgle

The fancy fountain
Bubbles on brightly
Blissfully oblivious

Light and dark
Bliss and bark
Guard each other well