Here's the "fish lying on the side" disease site!

http://www.fishvet.com/10.html said:

One of the greatest problems with this parasite in both the freshwater & the saltwater form is that most typically the Hobbyist will observe the infestation only when he sees a fish, sometimes more than one, gasping for air and in the last stages before death.


Usually this is when the fish is laying on its side on the bottom of the Aquarium, as it tries desperately to get air by attempting to breathe at the surface.

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