Fin Nipping

Question
I am currently housing a male betta, a red platy, and a
dalmatian molly in a 10 gallon aquarium.  I have a couple of
rocks and various plants for the fish to hide behind.  I
have a filter to keep the water clean, am using aquarium
salt for the water, and have a heater to maintain a constant
temperature (about 79 or 80 degrees) for the fish.  My
problem is that the betta (I assume) seems to be nipping at
the others' fins.  I noticed that a small piece was missing
from each ones' back fin.  The fish have only been together
in the 10 gallon tank for about 2 or 3 days.  Will this poor
behavior change for the better after the betta gets used to
his new company?  Is there anything I can do to quell the
fin nipping or is it hopeless?  So far it doesn't seem like
the betta is doing too much damage but I want to make sure
the bullying doesn't get out of control.  Thanks!

Answer
Male Bettas especially are known as aggressive fish who should be kept alone. Most stores sell them in single cups for that reason, they generally do go after other fish, especially if that fish has a tail that can be nipped at.

Most likely the Betta will not stop. The best thing you can do is separate the Betta from the others into a single tank, maybe a 1 gallon tank with a filter. Where it will be peaceful.

Also try to get a product called Stress Guard if you can and dose it into your tank. It will prevent infection on the other fish where the fins have been ripped and help them heal faster!

I hope this helps.