Question: How to Kill Hydra in a Freshwater Aquarium

  Options: 
 A. Hydra are related to jellyfish and are a common pest in home aquariums. Hydra are not generally harmful to fish, except they do have the ability to catch and consume small fry and shrimplets. Hydra are usually an indication of overfeeding, so feeding smaller quantities less often will help put a dent in their populations but their populations can be knocked out completely with a dose of common dog dewormer, available over the counter called Fenbendazole. Dose 0.1g fenbendazole per 10g of water volume. For heavy infestations, monitor water quality carefully after treatment to monitor for harmful ammonia spikes from decaying hydra.
 B. Hydra are related to jellyfish and are a common pest in home aquariums. Hydra are not generally harmful to fish, except they do have the ability to catch and consume small fry and shrimplets. Hydra are usually an indication of overfeeding, so feeding smaller quantities less often will help put a dent in their populations but their populations can be knocked out completely with a dose of common dog dewormer, available over the counter called Fenbendazole. Dose 0.1g fenbendazole per 10g of water volume. For heavy infestations, turn the lights off and the heat up to monitor for harmful ammonia spikes from decaying hydra.
Answer: A