I didn’t know that the American Christian movie industry had the resources, time or know-how to make a knockoff of Finding Nemo. I guess it makes sense considering it’s the religion of choice of the settler population there and is used as a cudgel to enforce “American values” or whatever.
First two apostles were fishers, and Jesus said that from now on they will become “fishers of men”, so fish is a symbol for christian beliver, with no bad connotations of other symbol, sheep.