Is she the only fish in the tank? If she is, then you may need to upgrade to a bigger tank and get her some friends. 2.5g seems a little small for anything more than a guppy.
Well, I went back to PetSmart today to ask them what was going on, and they said a 2.5 could house a molly and a platy, so I got her a platy friend. She's still stressing, but I figured out the source; it's the tank light. Is there anything I can do to help her get used to the light, or will it always stress her out like this?
You really should have a gallon per inch of fish. A molly gets roughly 3-4 inches, and a platy is the same. You should really have them in a 10g tank.
Oh, I plan on it, I just am waiting until my check comes in.
That's good. They will be alot happier in a bigger tank. I have a 40g livebearer community. They have great personalities when they are happy. Mine will come and nibble my finger tips when I get water for testing, and they always greet me at feeding time. They are very funny little fish.
I can already see their funny personalities coming out! My platy is very quiet and doesn't bother anybody, whereas my molly is constantly chasing him around lmao. It's funny. They definitely bicker back and forth.
My favorite Platy died 3 days ago. She was an original to my tank from when I first started. I still have her children though. I am pretty sure it was old age though. She didn't act sick at all. My parameters are fine and the other fish are healthy. Well, sad as it is. They don't live forever.
I'm so sorry for your loss.
Her legacy lives on through the babies I still have

They look just like her lol
Good, I'm glad you still have some of her left.

Just wanted to update: Derpette is doing well today. She's still a little nervous, but she came out to eat and swam around, picking at the plants and such. I think she just needs to get used to the lighting in the tank.
I also think she's preggo, her belly is getting roundish!
If you see her body taking on a slightly square shape, she is getting close to popping. As far as I know molly's don't eat their young, but Platys do. You want to add extra plants where you can so the babies have places to hide. And a bigger tank will be a necessity as they spawn often. The bigger the better honestly. I have 2 male Swords, 1 male MM Platy, 1 female Bumblebee Platy, 1 female Panda Platy, 5 Platy/Sword hybrids, and 5 platy fry. In a 40 gallon tank. I also have 4 albino cories and an Albino Bristlenose. I am close to being fully stocked, and my bumblebee had more babies last night, so I am not sure how many exactly are in the tank, I just counted what I saw lol. I get the feeling I will have an ad on craiglist in a month

If you have any questions, feel free to PM me or message me. I have gotten to knwo livebearers pretty well, and if I can't answer you, I will help you find the answers

I am glad your fishie is doing better. She probably just needed some time to adjust. My Betta was the same way. Most of the fish I have added recently don't have adjustment issues, as they are going into a tank with alot of friends, and alot of room. I don't know if that is why, or if I have been lucky.