In order to help a sick fish, we need to be able to determine the problem (diagnose). However, a diagnosis can not be used unless:


  1. The fish is showing distinct symptoms which are characteristic of, and unique to, a specific disease; or
  2. All other possibilities have been ruled out.


The only way that you can diagnose your fish is by analyzing their symptoms. While many symptoms indicate a specific disease (such as the white flecked, "salted" appearance of fish suffering from the external parasite), other symptoms are more general, and could indicate any number of different illnesses or problems. 


To illustrate this point, below is a table showing symptoms that you may see in an unwell fish, along with possible causes.


We have divided the symptoms up into:

  • behaviors that an unwell fish may exhibit, and 
  • physical signs of illness. 

We have also divided the causes into:

  • specific diseases, and 
  • problems with the fish's environment.
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Click to view full size

The Bottom Line

It is not always possible, based on observable symptoms, to determine exactly what is wrong with a sick fish.


Whether or not you can determine what is wrong, FIRST AID measures should be carried out for an animal that seems unwell.

  • Following these steps will provide your fish with an optimal environment in which to heal on his/her own; and
  • An environmental problem may have been the cause of the fish's distress in the first place - correcting the conditions will alleviate the problem.


Medication should NOT be given if you do not know what you are treating. There is no "catch-all" medication that will cover all possible illnesses, and giving medications indiscriminately will do more harm than good.