Hi David, It's Robert from Killitalk. The very best hydra killer is Flubendazole 5%. It has never harmed a plant in my tanks; does not color the water and works within 48 hours. Check Charlie Harrison's webpage. He sells it. Jehmco and Florida Fish Farmer's Co-op also sell it. Use 1/2 tsp per 30 gallons. Once the hydra are gone do a water change. It is wonderful stuff. Are you feeding baby brine to this tank? Usually baby brine causes a hydra outbreak -- they love the stuff. Gouramis work but are slow and you have to starve them a bit to get them to munch on the hydra. Robert Ellermann ------------------ To unsubscribe from this list, please send mail to majordomo@thekrib.com with "Unsubscribe aga-member" in the body of the message. Archives of this list can be found at http://lists.thekrib.com/aga-member/