Hi guys I am new here and new to the whole aquarium thing. I bought a 30 gallon tank kit. I have a filter, heater, thermometer, 2 pieces of 3 to 4 pound live rock and the proper lighting and i have one bag plain sand and the other is a bag of live sand. I also obviously put the right amount of salt in it also. I checked the water with a hydrometer and that came out good. I set everything up and let it rum like this for about 8 days. The I added a snail, peppermint shrimp and a Goby. A week later i just added in two damsels, i am not sure what kind if anybody can help me identify them that would be great. I am pretty sure I did something wrong as i have read that you are supposed to let the tank cycle? I am not really sure what that means. My understanding is that you just let the tank run for about a month to let the aquarium get used to everything or whatever. I called a petshop and they told me that an aquarium has not began to "cycle" until there are some fish in it which is why i just bought the two damsels. Somewhere alone the lline i think i have messed up. What is cycling and am i doing everything ok. One last thing, how do i keep my tank and fish healthy. I have no intentions of doing any reefs and just want to make sure im maintaining a safe and clean place for my fish. Thank you so much