I have an emergency hospital need for my 2 fish. I lost my only clownfish to Velvet and need to QT my only remaining fish (Blue Hippo Tang & Foxface) to treat with Copper Power and then leave the DT fallow for 76 days as recommended. Problem is my QT is only 15 gal. Can I place both fish for treatment and then for the remainder of the 76 fallow period for the DT? The fish are mid-size, about 3-4 inches each. I know it will be uncomfortable for them but I really have no other choice. Thanks