Introduction of Disease

[Boohoo]

With the many different diseases there are I don't expect a complete answer. I know that most diseases are brought into the aquarium by the introduction of new fish, but what diseases can just pop up at any given time without having introduced new fish lately? I don't have a problem that I am trying to solve, I am just curious about this.

 

[PumaWard]

Some parasites, bacterial, and fungal could all appear if stress is elevated.

 

[flyfly]

Pretty close to all of them, if not all of them, I would think. I mean, even the fish that are introduced with something got it from somewhere. Poor water quality is a disease magnet.

 

[OrionGirl]

Parasites will NOT just appear. They must be introduced, either through an infected fish, equipment, etc. Ditto viral infections--though you may have some viruses that come in on inrorganics, or through an infected water supply.

Bacterial infections are typically more prevalent, simply because a huge variety of bacteria live in tank (and other) water, but only cause a problem when the fish is stressed by other matters (ie, a parasitic infection, ammonia levels).

 

[SnakeIce]

while any disease including parasites like ich can pop up if a small undetected population exsists in a tank, it is entirely possible to have a tank or system of tanks where there is no ich. The tanks that are thought to have none and apon some stressor has a break out of ich has either had a population the whole time or it was introduced from a tank that also had a non-noticable population. ich does not spotaniously generate.

molds and fungus have spores that could come in on anything and the best cure is prevention.

It comes down to the fact that if you set up a tank in sterile conditions, culture every bacteria you add to the system to be sure it is desireable and pure, and house fish that have been raised in bacteria free environment, those fish will still be in poor health if the water quality is poor even without any of the usual symptoms and diseases we usually expect. That is why some people can get away with Aweful maintenance practices and still have fish that apear ok. No pathogens to take advantage of the poor health makes those fish look ok even if they are suffereing otherwise.