You have to build a pond in your yard. It doesn't have to be big, close to what is in the graveyard. I guess you could make it smaller, I don't know if there is a size limit on how small it can be to stock the pond. I prefer to have as big as I can on my lot so I cane make it into a quiet area, plants, a lounge chair.
If you have a sim who is a loner it's a great area to send him or her to relax.
Catch at least 10 of the deathfish and put them in the pond. This creates the stocked pond, do not fish in there until you have 10 fish. I prefer to have around 12 or more, but I think this is the minimum you need.
I don't remember if with those you can fish for during the day, someone else can answer that.