Changes in Weight:
Before you stress out about diseases too much, observe your fish at feeding time. The answer my be as
simple as another aggressive fish not allowing your fish to eat. It could also be that you are not feeding
the desired food. Check and make sure you are feeding a food that is designed specifically for your type
of fish. If this does not solve your problem, here are the most common diseases that affect fish weight.
Dropsy
This is a contagious disease and the affected fish should be separated from all other fish. The body of
the fish will be swollen. If caught early enough, the disease is treatable. Medication is available in
larger pet stores.
Swim Bladder Disorder
This disorder is caused when the swim bladder of a fish becomes damaged by disease or injury. The
fish may lose it's capability to float, stay down, or stay stable, seeming to tumble instead of swim. Since
there is no one cause of this disorder, there are several treatments ranging from the changing the diet to
surgery. Here are two inexpensive and cheap suggestions: 1. Put your fish on a 2-3 day fast. This
may give the bladder time to heal or if it is cause by an impaction, it could break down and pass. 2.
As strange as it may sound, feed your fish a pea. Again, if there is an impaction, this could help it
pass. For more detailed information on this see the following article.