Do you have salt in the water? If not I would use aquarium salt 1 tablespoon per five gallons. Remember to replace per water change. Salt will not evaporate but will be removed with water during a water change. Keep up on those water changes they can do miracles. Your stock list isn't very good either. You have fish that get huge mixed with fish that stay small. Research not trying to bust your !@@##$ but only trying to help.
