If the fish is acting "normal" and is just getting a fat tummy, it may be constipation which can usually be resolved with feeding peeled peas or other veggie matter. If he/she is swimming funny and has a large belly, that is probably dropsy. Here's something I borrowed from another site I trust:
Quote:
Dropsy usually takes one of two forms, body swells due to fluid accumulation, which causes scale protrusion, and also protrusion of the scales without the body swelling up, false dropsy.
Dropsy is caused by a bacterial infection of the kidneys and other internal organs, causing fluid accumulation or even renal failure.
Treatments are varied, adding salt at a rate of 5mg per gallon seems to help.
With modern Anti? Biotic this problem is soon cured.
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We also have some information on dropsy right here on FishLore
:
http://www.fishlore.com/Disease_Main.htm
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