platy behavior

Question
Hi and thank you.  I am very new to aquarium and fish care.  I just got my starter fish (3 platies).  One day after bringing them home, one of the females gave birth.  I think it was the Mickey Mouse platy.  The other female (not sure of her variety) is acting strange.  She will hide in a corner behind something occasionally darting out swimming around and then returning.  She sits on the bottom.  No rubbing noted.  She doesn't appear pregnant like the Mickey Mouse did.  This started yesterday.  She was eating.  This morning not so much.  She did manage a bite or two.  The other two adults seem fine.  The 12 babies that I rescued are also thriving.  They are 4 days old now.  I had my water tested 5 days ago and the fish store guy said it was fine, slightly high pH which is why he suggested the platy as a starter fish.

Answer
Hi Karen. This could be a few things.  Unfortunately, sometimes you just get the luck of the draw and get a sick fish.  However, sometimes the males badger the females into making them hide due to their never ending quest to impregnate females. You did not mention if you had a male or not, so I cannot tell for sure. I would suggest keeping an eye on the fish for the next several days to see if anything "appears".  If you have a hospital tank, I would separate them for the time being. If the fish does not look "better" or be acting better in another couple days, just do a follow-up for me and we can go from there. Please keep me posted, have your water tested again (Freshwater test kits are only about $20-$25), and please be sure to provide me with any and all information you can if/when you write back again.  Just be sure to keep a keen eye out and read as much as you can about disease so you can educate yourself on things to look for.

Good luck!