Male seahorse died, how do I keep his mate company?

My male H. erectus died from complications from GBD a few days ago. His female is doing fine as far as I can tell. I want to wait several weeks before introducing another seahorse into the tank just to make sure that she is going to be fine, but she is the ONLY fish in there. The tank is a 30 gallon tall tank with live rock. There are some smallish bristleworms in there, some snails, one hermit and her. Should I add some fish just so she will have some company of some sort, or just wait until time to add another seahorse?



Related question: If I got another female, should it be the same species or does it matter?



My plan is to wait a while then order a companion for her from the same source she came from.