Get yourself some welded mesh. Have a search on google for local supplier.
The one I used 3 years ago no longer exists. I went for 1" squares and about
3mm guage (thickness). I attached this to a wooden frame made from 2"x1",
attaching the mesh to the 1" side. I made this large enough to cover the
whole pond which is kidney shaped and approx 9' by 5'. The resulting frame
is strong enough for mee to wak accross (11stone) and way to heavy for a
toddle to shift.
I rest the frame on the rocks surrounding the pond a house bricks where it
rest on the path. That way frogs, newts & toads have easy access.

My daughter, nearly 2, can see the fish can lean on the mesh to feed them
and we feel very safe when she is in the garden with us.

Hoep that helps

AndyP

--
"Wisest are they that know they do not know." Socrates
"If more of us valued food and cheer and song above
hoarded gold, it would be a merrier world" JRR Toliken, The Hobbit