Could use a little more info on your tank before making reccomendations..such as :
Are there any other fish in the tank currently...?
Type of filtration currently using,
Any live rock in there now...?
How long has the tank been set up ?
Were you "cycling" with the hippo ?
Depending on what you have going currently will guide reccomendations for future set up...
In "general" LR can help in filtration, which can reduce water related stress which contributes to Ick...but won't keep them from getting ick if it's currently in the tank...