Not a classic, but one my father taught me early on...

AB, CD goldfish

L, MNO goldfish

OSMR goldfish

CMPN!

My mother thought it inane.

Jim, I knew a slightly different version. My dad taught me too:

AB, CD goldfish

L, MNO goldfish

Y, RC 2 goldfish

OS, ICM now.

For all the people who love puzzles! Lol

Done!

Mr ducks

O no Mr not

Os Mr

Cm wangs

I am not getting Jim’s or raven’s

Them are ducks=Mr ducks

OH no them are not =o no mr not

OH yes them are = os mr

See them wings =Cm wangs

I learned that one when I was very young.

https://www.reddit.com/r/funny/comments/53092m/m_r_ducks/

abcd goldfish? Abey see the goldfish?

LMNO goldfish Hell, them aint no goldfish!

OSAR! CMPN? Oh yes they are! See em peein?

Alternate ending for raven's:

CMEDBE Beeks?

LIB, MR Ducks

Yes there are a few different versions.

F U N E X?

S I F X

F U N E M ?

S I F M

OK LF M N X

From my father .