a4b972ab_m_and_Freshwater_Fish_Problems__Problem
[Symptoms] Tiny organisms are seen in tank [Solution] There are many small organisms which occasionally become established in an aquarium. Fortunately most are not harmful. They are often introduced with live plants. These organisms can include tiny worms, planaria, leeches, and crustaceans. Keep the bottom free of extra food an you will be able to control their growth rate. Sometimes copper sulphate solution or "Clout" will kill them. Corydoras catfish also help to keep small organisms from growing in the tank. [Problem] 
Unwanted "little bugs"
Aquarium and Freshwater Fish Problems
Problem