well the reason i chose to cycle with the green chromis is because they are supposedly the most peaceful damsels and i want to have them in there even after the cycle is complete. I used to have a domino damsel and it terrorized everything in my 10 gallon so i returned it to the fish store. I know there are other ways to cycle the tank like coctail shrimp and bottled ammonia but the Damsels can take it. besides my partially cured live rock was in for a few weeks first which cycled the tank a bit before adding the chromis.