I have a 30 gallon tank with rainbow cichlid, electric blue acara, pearl gourami, danios, cory cat fish and red eye tetras. Recently I have noticed some white spots on blue acara and rainbow cichlid's fins. Also the rainbow cichlid often digs into the sand substrate. One of the electric blue acaras now constantly hides in the plants and never comes out or eats. Could it be ich? If so how do I treat them?