SuomiBetta
Aquarium Advice Freak
Check in with Petsmart and ask. They all usually carry about the same stuff. If you ask at least you will know for sure you can't get any from them.
Luckily, my local petco has the rainbow fish No go with any of the four suggestions here (Scissor-tail Rasboras, Congo Tetras, Gold Tetras or Roseline Sharks)