Female Pearl Gourami is strongly bloated on one side
my female Pearl Gourami has been ill for about a week. A very big boil, shaped slightly angular at the back, has formed on the right side of the body gebildet. This boil is initself as thick as the female would usually be. Since then the fish has not been eating and reacts, as far as I can tell, with severe pain to the advances of the male.
possible causes include a swim bladder injury, an ileus or a tumor, possibly also a cyst.
Sudden occurrence (i.e. not a continuing development of the symptoms) would make a swim bladder injury likely. This can unfortunately not be treated, it can be caused, for instance, by severe attacks from other fish.
An ileus may occur if the fish swallowed indigestible matter (e.g. plastic or styrofoam parts). There is also no treatment in this case, this is almost always fatal. Belly bloating takes place within a few days, even if the fish does not eat any more.
Tumors and cysts may have different causes ranging from bacterial infections (e.g. fish tuberculosis!) via encapsulated higher parasites (e.g. metacercaria, these are worm larvae) up to real tumor diseases including cancer. Treatment is usually not possible, but the symptoms do in most cases not develop within a few days. Ovarial tumors in female fish do in fact not occur that rarely.
The symptoms occurring on just one side make it unlikely that this is a case of dropsy (which is the symptom of a severe kidney infection), whereas the bloating is usually rather symmetric in case of dropsy (this is best visible when watching the fish from above, please refer to the corresponding picture in the section "Diseases caused by bacteria" in our guide "Healthy aquarium fish", available for free as a PDF in the download section).
Dr. Bodo Schnell