Did you ever see a fishy?

Did you ever see a fishy? - song (to tune I know as "Three Cheers for the Bus Driver" - actually called "Did You Ever See a Lassie" - thanks, Leslie for that reference!)

Did you ever see a fishy, a fishy, a fishy?
Did you ever see a fishy go this way and that?
Go this way and that way
And that way and this way
Did you ever see a fishy go this way and that?

Yes, I've seen a fishy...