I have a Bolivian Ram in my 10 gallon and 2 Kribensis cichlids in my 40 gallon. They are all alive, active, and healthy and have been for a year. I drip acclimitized. This is the the drip acclimitization setup that I used. I drip acclimitized them over a 2 hour period with the tubing set to one drop per second of tank water.
http://www.aquaticplantcentral.com/f...on-set-up.html
Besides drip acclimitizing them, I think you should be fine as long as you purchase healthy ones from a reputable seller. Ask the seller how long the fish have been in the tank. Generally speaking, the longer the fish have been in the tank the healthier and more hardy they are likely to be. The weak and diseased ones will be the first to go, usually with a few weeks to a month of being in the seller's tank. And don't buy any fish from a tank where you see even one dead fish in the tank. A dead fish in a tank is never a good sign and if that fish died of a parasitic infection and has been laying in the tank for days or even hours you can be guaranteed that the parasite may be water borne and may have likely infected other fish, especially so if you see other fish feeding of the dead fishe's diseased carcass.
For reasons mentioned in this article
http://www.bestfish.com/tips/050798.html and based on my own experience of losing more fish in general to the bag float method vs drip acclimitization, I tend to use the drip method.