How to introduce a new crab to my current crab?

[crabmilf]

I've had my first hermit crab, Hermi, for over a month now, and I just adopted another E to be his companion! I would like some advice on how/when to introduce them.

I brought home my second crab, Pearl, yesterday from the pet store, and she was sorta freaking out for the whole 40-minute drive. The conditions of the pet store were not ideal at all - an open tank with no heating pads, humidity, substrate, too many crabs, and anyone could pick them up. (I usually would not purchase a crab from this kind of store, but I have been having a hard time finding an E, but I was scared my first crab would get too lonely.)

I set her up in a temporary enclosure as soon as we got home with some substrate (not enough to molt yet), two baths (both dechlorinated treated water with one salt water and the other fresh), made her a balanced snack bowl, a heating pad, and some leaves to hide. She seems to be enjoying her new enclosure. I saw her eat and soak in the salt water for a while. But mainly, I left her alone last night.

My plan was to introduce her to my main tank with my crab Hermi tonight after they have both been fed. However, I have seen conflicting advice on the hermit crab sites I have frequented. Some say you should set up another isolation tank and allow your new crab to molt before introducing them to the main tank, but in most of those posts, there are already multiple crabs in the main tank, not just one. Hermi has been staring at himself in the reflection of his tank, and I think he is lonely so I don't want him to be lonely for too much longer if possible.

A few other notes for context -
- Hermi molted almost immediately when I placed him in his new proper tank. He was in temporary setups for a few days after I got him as I set up a new tank, so his conditions gradually improved over the course of four days.
- Pearl seems to be missing a leg and maybe an antenna, so it seems a molt is in order.

I am leaning toward setting up a full isolation tank for Pearl to molt properly before I introduce her to Hermi, but I appreciate your thoughts.

Thank you for your input and advice!

[hermitsssss]

when introducing your crabbies, make sure you have plenty extra shells and space- dunking both crabs in the same water will get them to smell like each other, so they will be less aggressive(from what i have heard) i would introduce them slowly, and watch them when they are together for awhile, make sure you have lots of placed to hide as well, in case of the worst case scenario. pearl will probably be very shy at first, but most likely they will grow to be buddies you could put a clear barier between them for the first night, thats what I do, then let them be in the same area during the day(as long as you check on them every now and then

[curlysister]

As already stated, dunking both crabs into the fresh water will make them smell the same and nobody seems like an interloper. And to have lots of extra shells, especially if they are of similar size.
There is no evidence that any specific 'method' improves survival rates for new crabs. If you do set up an isolation tank, be sure that it has proper conditions, including heat, humidity, and deep enough substrate to molt. And then you would still need to introduce them by dipping in water, observing for aggression, etc. I would say that most of us long term crabbers generally don't isolate new crabs when we get them.
Be sure to check the E care sheet - they do need deeper sub than PPs.