More info on oscar in heat

Question
QUESTION: Sorry I forgot to mention that she/he is in a 55 gallon tank with a couple smaller cichlids and a placostomas.  I do not know anything about the water.  I don't know how to test for it.  I recieved the tank from a friend who were just going to get rid of them.  Generally try to change the clean the tank at the most every other week, every once in a while has gone 3 weeks.  I just continued feeding them what the previous owners were, a pellet for the oscar and then flakes for the other fish.  Hope this helps a little more.  Thank you

ANSWER: Hello,
An Oscar needs a 55 gallon tank all to herself.  You must keep the tank very clean.  Common Placostomas can grow to 25 inches, so will eventually be to big for your tank, and no Pet Shop to my knowledge will take it back.  Your Oscar should be alone in this tank, and water changes every week of 30% are a "Must."  Failure to do so will results in poor water conditions.   When ammonia, and nitrates set in the water, disease happens, and sometimes death.  You can buy these small kits at your Pet Store, and they are handy to have, as you must check you water for ammonia, and nitrates at least once a week.  From what you have told me, I am quite sure that your water chemistry is bad.  Do a 50% water change using a good conditioner such as "Stress Coat" or "AquaPlus"
Bring your other fish back to the Pet Store, and get a credit.

Your Oscar seems to have Swim Bladder Disease which is caused by poor diet, and overfeeding which leads to constipation, and then SBD.  If left untreated, this may turn into dropsy, and dropsy is very hard to cure if not impossible.  Feed her frozen peas that you will cook until tender, and let cool.  Do not feed her anything else for two days.  She must waste.  If in two days she has not wasted, you will have to treat her with an antibiotic.  "Kanamycin" is very good for swim bladder disease, but sometimes hard to find.  If you cannot find it, buy Tetracycline, or Furan 2.
The main thing now is to bring your ammonia level down to zero, and nitrates to safe.  You will have to buy these test, as curing fish in water that as ammonia or nitrates in it won't help.
Do a 50% water change, check to see if you still have ammonia in your water, if you do, tomorrow, do another 20% water change, and check again..keep making water changes everyday until you get the ammonia level down to zero.
When your Oscar is better, vary her diet as much as possible.  They love veggies, so give her broccoli, green beans, peas, and carrots that you will cook.  I buy mine frozen, and take out what I need, and blanch them.  She needs insects such as crickets, ants, and cleaned worms.  To clean the worms, put them in oats for a week or so.  Oscars need a good quality flake, and frozen foods that you find at the pet store.  You can also buy her fish that come from rivers or lakes,(Never salt water fish) and feed it to her raw, and defrosted.  When feeding pellets they should always be soaked a little before feeding them to her, as this makes it easier for her to digest.  Never feed her feeder fish as they have no nutritional value, and are mostly always full of disease.
Feeding her well, and keeping her tank very clean with no ammonia or nitrates is a must for her to be healthy, and happy, and live a nice long life.
I hope I have helped you, and if you have any other question, please do not hesitate to write me.  I love Oscars!
Lynda

---------- FOLLOW-UP ----------

QUESTION: Thank you, this definitely gives me a way to go to help her.  How much should I be feeding her during this time.  A handful of peas, just a couple?  And after hopefully she gets better... after reading other posts sounds like this can be pretty serious, should I be feeding her the same amount or more?

Answer
Feed her 4 peas now, and 3 peas later on tonight.  This should help her.  Tomorrow, you could feed her 4 more peas.  Remove the outer layer of the pea once it is cooked.  Hopefully she should waste.  Poor Oscar, I am keeping my fingers crossed, and will say a little prayer for her.
Keep me posted on how she is doing please.
Lynda