Yes i believe it is cycled, a good friend of mine put it all togeather, he has 15 saltwater tanks and added live rock and sand from his tanks. Her told me to just get a couple of damsils for about 4-5 weeks but could only get a couple of clowns. Was having trouble with algae so he had me get a bunch of crabs and snails so i ordered the package and all seem to be doing finel. Thanks for letting me know about the clowns...Wish me luck, my first saltwater tank and really fun.