Definitely! In my opinion I don’t think freshwater tanks should have plastic decorations either. The fish come from natural streams and lakes that contain live plants, algae, wood, and rock - those four things should be in the tank instead of plastic; plus it’s more visually appealing.Best “decorations” for saltwater tanks are live rock and corals! Not like the weird stuff freshwater tanks have lol. Those kinds look tacky in saltwater in my opinion, detracts from the fish and their colors!
As for the saltwater tips: definitely research and get a good foundation in how to take care of saltwater fish prior to purchasing them. If you already bought the fish then I’m hoping you cycled it with bacteria prior to introducing the fish or have established live rock in the system to convert the ammonia to nitrate.