what type of cement to use for pond?

I am putting a new pond in my back yard. It is my first time doing a
project like this. I have pretty much got the hole dug at about 3'5"
and i have already purchased the rebar. My problem is that i cant seem
to figure out the best type of concrete to create a liner. I was told
gunite and portland. but im not sure. Also will I have to seal it
regardless of what type of cement i use? Soo many questions. Also if
anyone has any tips i would appreciate any help on sealing the drain
or plumbing tips.

Thanks in advance.