WANTED: Small friendly community fish

Hello, can anyone direct me to fish safe wall blocks that I can use to stack a wall inside of the pond liner. My pond rebuild will wrap around half of my patio (curving) so I want to be able to look down all the way into the pond. Something nicer than cinder blocks. Also what type of mortar or construction adhesive that is fish safe? Thank you for all suggestions!

I need a female but preferably eggs/multiple juveniles

Any free fish going in Nottingham

Anyone rehoming any small friendly/ community fish Warrington area please