Don't worry, ich is fairly easy to treat.
However, since ich infects the entire tank, you need to treat the entire tank.
Step 1) Change out half your water (or more) so you start with good water parameters
Step 2) Increase the temperature to 86 degrees slowly over the course of 1-2 days, this will help prevent the reproduction of ich and speeds up the cycle.
Step 3) Dose with Copersafe, this should not harm most plants. Make sure you dose for actual gallons of water, not what your tank's rated capacity is. For example, in a 10g tank dose for 8g.
Step 4) Do nothing for 1 week, this includes not adding plant fertilizers. Plant fertilizers can contain copper and you don't want to increase those levels.
After a week, observe your betta closely and ensure no spots remain (most if not all should be gone by day 3).
Do not do water changes during that week unless you have ammonia/nitrite problems (uncycled tank, or too small tank). If you must do a water change, dose the new water with the appropriate amount of Coppersafe so you don't dilute the medication.
I'm assuming you do not have any inverts, copper can be deadly to inverts. Some people have had problems, others have not... it's your choice if you want to quarantine the inverts for 3 weeks or let them risk it.
Last edited by Geomancer; 02-14-2012 at 10:18 AM.
Reason: Adding more details/clerification