New brackish tank

First off, please pardon me for not using scientific names to describe what's in my brackish tank.
I have a 55 gallon that I'd like to make look marine or reef-like in its appearance. I can't use real plants but does anyone have any suggestions I can use?
Thanks

Believe it or not I do not know very many of the names of the fish we got because I can't read the fish store owners handwriting
She has run this fish store in her home/basement for 35 years and is the best! We won this 55 gallon tank in a raffle she has every year. I have a 29 gal. freshwater tank also.
Anyway, I know we have a silver scat, a mono...9 fish all together, only 1 of each. She told us to see which species we like and then to get two more of them...either have 1 or 3 or 5 of a species.
I did get some beautiful fake diftwood, artificial coral & anemonies but I would like some plants that are specific to reef/marine tanks. All I can find are freshwater ones.
Thanks for the replies...I am new here.