Our first saltwater fish

A Damsel, but hopefully not in distress: We were obliged to get a Yellow Tailed Blue Damsel as out first fish since they are hardy, and I'm a nincompoop when it comes to saltwater maintenance. I did a 25% water change the other day and didn't bother to check the Alkalinity/Ph of the water from the store and it made the Xenia pucker up like it licked a lemon, but the Damsel seemed unaffected.