Join Date: Aug 2011
Location: San Bernardino, California
She might be stressed out. What size aquarium do you have them in?
They need lots of cover and places to hide. If you're just going to keep the two of them then they should alteast be in a 5 gallon heated and filtered tank. Make sure there is a lid because they can jump out. If you plan on getting 2 more then you'll want a 10 gallon aquarium.
Use API Stress Coat, you can get it at PetCo or PetSmart, you may be able to find it at your local fish store (LFS) as well. Use it along side or have it replace your normal Water Conditioner. Two cap fulls will do the trick.
Your tank MUST be heavily planted with plenty of places to hide. Silk plants are always better then plastic plants when it comes to Bettas.
If she is sitting at the bottom then she might just be the submissive one of the two, she could just be staying still trying not to provoke the other female.