Fish Diseases

When we become sick we are able to tell other people where it hurts, what is wrong etc. Fish however do not have that ability therefore it is up to the aquarist to attempt to identify potential problems as soon as possible and provide the relevant treatment as and when it is required to do so.

As both myself and John state again and again – stability, patience and research is the aquarists key to success. If this is performed then the risk of disease is reduced. It is not removed altogether but is reduced.

Marine fish of every type are said to carry some type of disease or other as the majority of animals do. All it takes is something to trigger it.

The most common trigger for diseases is stress. Stress is quite often un-noticed by the inexperienced aquarist. Unbeknown to them a disease is starting to show itself. If not identified and diagnosed quickly enough then this could cause trouble in the aquarium as well as distress to the fish in question.

What happens is that when the fish is placed under stress the immune system of the fish weakens therefore the fishes susceptibility to disease increases.

The majority of home aquariums have a low pathogen count present – normally the immune system of the fish will prevent these pathogens from causing problems.

However when the immune system is weakened the risk increases. There are various ways in which stress can be placed upon the fish:

  • General water quality is not good enough
  • Fluctuation in parameters, heat etc
  • Bullying and/or territory protection from other tank inhabitants
  • Overstocking
  • The aquarium in which the fish are kept is too small for the fishes needs
  • Limited hiding places
  • Reduced oxygen in the water
  • Incorrect feeding techniques
  • Shock

When the fish is caught in the ocean and is transported to the shop via the dealer we of course have no control over that but hopefully the fish will be placed under as minimal amount of stress as possible.

We do have control over the stress caused to the fish from the moment a decision is made to purchase it.

From this point forward we have the ability to be able to reduce the amount of stress the fish is placed under. We can ensure that it is transported correctly, quarantined correctly, acclimatised correctly, is not with incompatible fish in the aquarium etc.

There is a keyword in the above sentence which I believe is very important and that is the word quarantine. It surprises me to this day how few people actually use a quarantine tank on their aquarium.

Once the fish is in the display aquarium it should be monitored closely especially during the first few weeks to ensure that it is not being bullied, feeding well, active etc however during your regular maintenance you should ensure that you check each and every fish in the aquarium. If you spot a problem early enough then it is much easier to deal with.

When you study your fish’s actions from arrival you will quickly see what is normal and what is not.

When observing your fish watch carefully for the following:

  • Fish not feeding
  • Fish scratching against the substrate and/or decor
  • A normally active fish is subdued
  • A normally subdued fish is active
  • Fish not swimming correctly
  • Fish at the water surface gasping
  • Visible marks on the body of the fish

Of course you can perform all of this and still get a disease in the aquarium however as said looking after the aquarium correctly, choosing and caring for fish correctly will reduce the possibility of an outbreak.


Fish Diseases
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