Two neon tetras lost tails and died.?

  Other neons seem ok. No other fish in the tank, only 2 shrimps. I was advised this may be result of bullying, but haven't seen the biting going on. Can I do anything to help? I have placed more plants in the tank for cover, and hiding places. Is there anything else I can do?
it could be fin rot. monitor the otehr fish and quaranitne them if they start to have shredded fins and treat with maracyn or a similar product.
I agree with Angelfish. Sounds like a disease.