Hey I'm building an artificial habitat out of a half-sunken yacht on my property and I've recently caught a dhelmise that I'd love to let access the habitat but I'm not sure how to socialize it with the other pokemon in there. Any tips?
Half sunken yacht on your property?? Dang, must be nice to have the money for yachts and property.
Anyway, Dhelmise is a fairly unflappable pokemon, you could theoretically just plop it down anywhere and it'd be fine, but it's always a good idea to properly socialize your pokemon! Make sure to keep it well-fed while it's still settling in (real marine snow can be hard to source but any aquarium store worth its salt should have 'filter feeder food' made of plankton, that's what you'll want), and if you have any Skrelp or Dragalgae, introduce them first. They tend to get along very well, and wild ones have been known to engage in mutualistic relationships! The Skrelp and Dragalgae provide seaweed and detritus, and in return Dhelmise gives them a safe place to hide and anchor themselves. It's very cool to see for yourself.
Also make sure to keep big pokemon away from it for a while (we're talking, like...twice the size of Dhelmise itself or larger), at least until it knows that these pokemon are friends, not food. It sounds reckless and weird for something to predate on things much bigger than it, but remember, Dhelmise is a seafloor dweller and a ghost/grass type! The most beneficial thing it can do for itself in the wild is cause a whalefall, and it absolutely will if you give it the chance. Don't give it the chance, if it attacks a Wailmer or Wailord in a pod that entire pod will come down on it and everything around it with all the fury of up to thirty very angry, very large whales. I will perhaps leave it at that because I've never seen that kind of destruction and frankly I don't want to.
Anyway, hope the project goes well, do your local biologists a favor and allow them access to your project so they can observe it, there's a lot of undergrads that REALLY want to study the ocean floor but have issues finding ways to really look at it, and Arceus KNOWS we know less about the bottom of the ocean than about the surface of the moon.