>>33267432
You have to have the patch that added them. Then you have to wait until I think year 2 and find the mermaid statue in the non financial buildings, and drop it in a tank. Each one you drop becomes a mermaid.
The patch is included in the versions of the ROMs you get from myabandonware btw, and there is a comment on its page with I think 6 steps to install and run it. It's basically just get daemon tools lite, use it, and install, and some troubleshooting stuff

Also here is my summarized writeup of all the cheat codes I found from a few sources, I haven't tested them all yet but I know at least some of them are legit from when I used to play

>>33267437
Fair enough, I need two more names now