Disease in ornamental fish

Despite this, many diseases in captive fish can be avoided or prevented through proper water conditions and a well-adjusted ecosystem within the tank.

Diseases can have a variety of causes, including bacterial infections from an external source such as Pseudomonas fluorescens (causing fin rot and fish dropsy), fungal infections (Saprolegnia), mould infections (Oomycete and Saprolegnia), parasitic disorders (Gyrodactylus salaris, Ichthyophthirius multifiliis, Cryptocaryon, Oodinium causing velvet disease, Brooklynella hostilis, head and lateral line erosion, Glugea, Ceratomyxa shasta, Kudoa thyrsites, Tetracapsuloides bryosalmonae, Ceratomyxa shasta leeches, nematode, Trematoda, Platyhelminthes and fish louse), viral disorders, metabolic disorders, inappropriate water conditions (insufficient aeration, pH, water hardness, temperature and ammonia poisoning) and malnutrition.

Common preventive strategies include avoiding the introduction of infected fish, invertebrates or plants by quarantining new additions before adding them to an established tank, and discarding water from external sources rather than mixing it with clean water.

Similarly, foods for herbivorous fish such as lettuce or cucumbers should be washed before being placed in the tank.

Other alternatives include short baths in a bucket that contains the treated water.