Perhaps they were dancing, tripped, and fell:

"Will you walk a little faster?" said a whiting to a snail,
"There's a porpoise close behind us, and he's treading on my
       tail.
See how eagerly the lobsters and the turtles all advance!
They are waiting on the shingle—will you come and join the
       dance?
    Will you, won't you, will you, won't you, will you join the
       dance?
    Will you, won't you, will you, won't you, won't you join the
       dance?

"You can really have no notion how delightful it will be
When they take us up and throw us, with the lobsters, out
       to sea!"
But the snail replied, "Too far, too far!" and gave a look
       askance—

Said he thanked the whiting kindly, but he would not join
       the dance.
    Would not, could not, would not, could not, would not join
       the dance.
    Would not, could not, would not, could not, could not join
       the dance.

"What matters it how far we go?" his scaly friend replied.
"There is another shore, you know, upon the other side.
The further off from England the nearer is to France—
Then turn not pale, beloved snail, but come and join the
       dance.
    Will you, won't you, will you, won't you, will you join the
       dance?
    Will you, won't you, will you, won't you, won't you join the
       dance?"

Or, perhaps more to the point,

'Tis the voice of the Lobster: I heard him declare
'You have baked me too brown, I must sugar my hair.'
As a duck with its eyelids, so he with his nose
Trims his belt and his buttons, and turns out his toes.
When the sands are all dry, he is gay as a lark,
And will talk in contemptuous tones of the shark;
But, when the tide rises and sharks are around,
His voice has a timid and tremulous sound.