Platy not well

Question
Hi and thanks in advance for your time.  I have a female platy that isn't acting well.  Water parameters are good with bi-weekly water changes.  She looks fine other than being just a little thin.  She has always been a little small.  She seems to be having somewhat of a little seizure.  She'll tilt her body just a bit and shake for a second or two.  She also swims backwards a bit when she does this.  Do you have any idea why she might be doing this?  She is harrassed a good bit by a male in the tank, he usually keeps her in hiding.  Any advise you have would be greatly appreciated.  Thanks again.

   Matt

Answer
Dear Matt,
Sorry to hear about your platy. Just to be one the safe side, first off i'd do at least a 30-50% water change just to be sure water quality isn't the issue.

I wonder if her behavior is what is commonly associated with livebearers called "Shimmying" this is when the livebearer (platy, ect...) typically stays in one place while wagging her tail back and forth. They often do this near the top of the tank. Shimmying can be sign of poor water quality which of course means a good water change. It can also be the beginnings of an illness like dropsy so watch for that. But be sure to eliminate other possible causes by doing water changes, making sure the water is warm (at least 78-80F) and limiting stress levels. She may be simply overstressed by the aggressive male. The poor females of any livebearer species are almost always doomed to be constantly pestered by the males often to the point of forcing the female(s) to hide on the time. Besides removing the aggressive male into another tank, the next best thing is to provide as many visual blocks and hiding places as you can in the tank. Probably the best visual blocks are thick and tall plastic plants. Even so, I have found that persistant males will often hunt the female down even if she gets away and hides. It's a very sad sight to see and many female livebearers are only in peace in a tank with just no males.

I don't really like to diagnose diseases or prescribe any medications just yet. The best thing you can do is several water changes, try to add more plants perhaps, and watch her closely. I noticed you said she looked a little thin, this is really unusual for a female platy since they are almost always pregnant especially in a tank with a male. If you notice stringy white droppings coming from her this could indicate internal parasites along with her thin. Fish with internal parasites may or may not eat, sometimes they will be off-color and generally will act poorly. Medicated food is best route to take along with a water treatment of Melafix/Pimafix combination. But I'm not exactly saying this is what your fish has but it is definitely something to watch out for.
You will be the ultimate one to provide the best diagnosis since you know your fish best and their symptoms.

I really hope this helps!!
Best of luck!
Karen~