Maddie wrote:

1 - Can I keep a cleaner shrimp in a FO tank given that I won't be using RO
water anymore and my water quality may not be quite as high as it was in my
reef tank?

Yes.

2 - What are suitable tankmates for my 3 inch percula clown in my 30-gallon?

I would avoid triggers, tangs (except yellow tangs), most damsels, and anything
that might get too big. A dwarf angel or dwarf lionfish might be good. I would
probably opt for a flame angel.

3 - How many fish can I keep in a 30-gallon? I seem to remember a certain #
of inches of fish/gallon.

The general ROT is 2-3" of fish for every 10 gallons. So, a 30 can take 6" to 9"
of fish.

George Patterson
All successes in conservation are temporary. All defeats are permanent.