Put a few plants, real or fake into the tank and let her get her exercise with that filter. The plants will give her a place to rest and the filter flow will give her a place to exercise. This guy lives in a 45 gallon tank with a canister filter that pushes at least 5 times as much as your little HOB filter and he is just fine. It did take him a while to get strong enough to just swim right through the filter flow though. During that time he just stayed out of the main part of the current.