Not sure about LFS, but you will want to visit Mandalay Bay for their saltwater exhibit $16.95/adult I think.
http://www.mandalaybay.com/entertainment/sharkreef.aspx
You may also want to visit the Mirage...they have a huge (one of the worlds biggest) SW aquarium behind the front desk. No real coral but tons of fish behind a 4" thick acrylic wall. It's really pretty new (I saw the old one before they renovated and it was cool)
Just some ideas though.