Fish behaviour and death

Question
QUESTION: Hi Jenny,

I currently have (had)two adult female mollys Freckles and Blackjack.  We have 10 babies also. They are in a 10 gal fish tank.  This morning everyone was eating and swimming and happy.  About 15 mins from the last time I checked on them I found Blackjack dead on the bottom of the tank.  I cried my eyes out.  What happened to her???? Second question/ Freckles is swimming frantically up and down and in circles where Blackjack died.  Is this normal?? We are going to our petstore tonight to find another molly to keep Freckles company.  I hope I am doing the right thing.  I am so sad.

ANSWER: Carman:
There are really no symptoms of why Blackjack died. It could have been a bad thing he ate that was poisonous or maybe something large was sucked into his gills and got caught in his inner body (very rare and freakish). I am so sorry and I hope this will never happen again. I recently had my goldfish, Yolanda, die, and it was quite painful as well.
:(
-Jenny

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

QUESTION: Jenny,
You didn't say whether or not freckles behaviour was normal or not.  Also, blackjack was a girl not a boy. When is it ok to add another adult molly to my tank to keep freckles company.  Will she be aggressive?  I am consured if I get a diff color or species molly freckles will try to hurt her.  Should I get a boy or a girl to keep her company?

Answer
Carman:
Freckles behavior is quite normal for the death of her buddy. You can add another molly anytime, preferably female. You should get the same species and gender as Freckles, so they have a lot in common and they won't be so foreign to each other. Sorry for my lack of answering your previous question.
Good luck!!
-Jenny