Flux Rx is an extremely safe and effective aquarium treatment and can even be used in reef aquariums with corals present. It should be noted that if you have bryopsis or green hair algae present in your aquarium, fluconazole can cause rapid death of these algae species as a side effect. Hair algae can bind significant amounts of nutrients in their tissue, and if they begin to die, they will release these nutrients, including nitrate and phosphate, back into your aquarium, so you should be prepared to perform water changes and take other action to maintain water quality.