[Lurker rises]
I know little about ponds, but is your wall as it seems, dry-laid
block, or did you use mortar and tie it into the landscaping?
rebarbed and cemented into the ground

Are you
in a climate that gets rain or snow?
yes

As for the fence on your side you must protect your children and
visitors.

a fence will go up
People in the next town over lost a 16 month old to drowning
in a 2 foot pond.
our worst nightmare

[Lurker sinks back into the pool]