sick oscar

Question
i hav 2 oscars and 2 japanese koi in a 200 litre tank dimensions 1.2mx600mm. the oscars are 8 years old. the 1 oscar which i think is the female has pop eye, bloated stomach for almost 2 weeks and today i noticed that she has a bubble-like translucent ball at the anus area which probably happened over the wkend. she has also not been eating and floats vertically at the bottom of the tank. Struggling to breathe im assuming due to her constanting having her mouth open and the gills flapping open v.wide. i am battling with my fish being sick for over a week, and trying the suggestions of the pet shops doesnt seem to be helping. i used myaxin for 5 days and changed water in the tank leaving 25% before using the myaxin. there are 2 filters, one of which is aqua300. the heater is set at 26 degrees celsius. can u please help me, i dont know wat to do and im afraid of her dying?

Answer
Hi Nivashni,
 Unfortunately it doesn't sound good for your oscar.  I strongly suggest that you do more water changes. If it were me, I would change 25% of the water every day for the next 3 days or so.  Then I would look carefully to see if the other oscar is attacking her.  Sometimes that only occurs at night.   

-- Ron C.
  rcoleman@cichlidresearch.com
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