Hi Kathy, I have successfully treated hydra in a shrimp tank with Fenbendazole which I got from Kevin at APFP. Here is the link with the instructions that I used. http://www.aquaticplantcentral.com/forumapc/library/52784-planaria-hydra-eli mination-shrimp-tanks.html Roy _______________________________________________ GSAS-Member mailing list GSAS-Member@thekrib.com http://lists.thekrib.com/mailman/listinfo/gsas-member