Fungi affect the physiological conditions of animals as well as plants by decreasing their activities. Fishes are one of the victims of the fungal infections. In aquariums, ornamental fishes get infected with different species of the fungi due to several factors.
          To avoid such infections to fishes, several commercial chemicals are available in the market. The current study is to replace these chemicals with plant extracts. The number of bioactive molecules present in plants makes them an affluent source of variants of medicines. In the present study, antifungal activity of medicinal plants Parthenium hysterophorus, Achyrathes aspera, and Catharanthus roseus was assessed against Candida sp., Penicillium sp., and Aspergillus sp. isolated from infected aquarium fish. In the present study it was found that as compared with the zone of inhibition obtained in the standard tests, the maximum inhibition was exhibited by ethanolic extract of Parthenium hysterophorus and Catharanthus roseus against Aspergillus sp, chloroform extract ofParthenium hysterophorus andCatharanthus roseus and ethanolic extract ofAchyranthes aspera against Candida sp while ethanolic extract of Parthenium hysterophorus, Catharanthus roseus andAchyranthes aspera againstPenicillium sp.