Question about clean up crew

I am still cycling a new 45g tank with LR. No fish yet but I am bored now and wanted to know when should a crew up crew be introduced and what kind of make up would be best for a 45g.



The only fish that I know for sure I am getting are 2 Ocellaris Clownfish. Still looking/researching other fish to put in with them.



Thank for any info