Sick Platy - Please Help

[cherrylee10]

Hi,  I am new to the forum and really need some advice.  I have 4 platies, 3 female and 1 male.  I got them at the same time 6 weeks ago. Right from the get go one of the platy was very shy and always seemed to hide.  She did eat for the first few weeks but I haven't seen her eat for about 3 weeks.  I put her into a smaller tank on her own for a while to see if you she eat but she did the same thing in there. 
 
About my tank:  I have a 20 gallon tank with 4 balloon mollys, 3 albino cory, 4 neon tetra and the 4 platy.  I test the water weekly and the ammonia is 1.2 and nitrite is 0.3.  All of the other fish seem very happy, I have a lot of pregnant females and some balloon molly fry in a breeding tank floating at the top of the tank.  I haven't lost any of the fry and they seem to be growing really well, I thought this was a good sign that the water is ok.
 
None of the other fish seem to bother the sick platy but she literally looks like she is wasting away.  I have looked for diseases on33line but I can't find anything that describes how she looks.  She doesn't seem to be able to close her mouth properly and there does look to be some red blotches around the mouth. 
 
Any help at all would be great
 
Claire

 

[PrairieSunflower]

You should be aiming to keep your ammonia at 0.  I.2 ammonia is really high.  You need to do some water changes to get that ammonia down.
 
You said you've had the platies for 6 weeks, but how long has your tank been set up/cycled?

 

[cherrylee10]

Hi,  Sorry the ammonia should have said 0.2 not 1.2.  I have been doing water changes once a week of about 25%.  I had the tank set up for about 2 weeks before I added the platy.

 

[PrairieSunflower]

So you began a fish in cycle after 2 weeks.  Did you do daily/frequent water changes during that time?  15 fish is a lot to add to a non-cycled tank.  I would guess you actual cycle may have only ended recently.
 
It is possible this platy was more sensitive to the cycling than the others and may have suffered some damage.
 
Perhaps someone else can chime in about how to help your platy.  Is it at all possible for you to also do a close up photo of her mouth area?
 
 
Platies are my nemesises... I can't personally seem to keep a platy healthy... so I am probably not going to be much more help than that.