Hells bells and little fishes

"Hells bells and little fishes." (Mother was born and raised in London and remember using the phrase; she doesn't know if it has a valid origin or whether she came up with it herself. - she is 96 now) Any help greatly apreciated.
My thanks ....

I'm from the U.S. and have never heard of it. But I'll be using it from now on. I am wondering if "little fishes" refers to the loaves and fishes that Jesus used to feed the multitudes.

It's certainly a phrase that I was brought up with. It's still current, but not common. I have no idea of the origin.
There's another similar 'hells bells and little bodkins'. Again, no idea where this came from.
A Google search shows many variants.

My mother used to use "and little fishes" too. 1930s Home-counties upbringing.

L