Guppy tail seems to hang down at an angle and she sits on the bottom alot, taking a while to notice the food.?

Question

Also seems to be breathing fast and possibly some red coloration around the end of the tail near where it fans out (but ignore that part if it bears no relevence because those might just be colors that have always been there)

Answer 1

It means it's sick and it is about to die.

Answer 2

Have you checked your water? Sounds like you've had the fish awhile  so I doubt it's because you didnt add conditioners.

I'm betting the ammonia is running high. I suggest a 50% water change (treating the new water of course)

Check your levels! Something is high. Check them again tomorrow after you do the water change, you should see a difference.

Hope this helps!