they do, but if you have no experience with any kind of fish, i suggest starting with a freshwater tank. marine tanks are very expensive. i have a 30 gallon biocube. my price range is about, 400$ in equiptment, 200$ in corals and 300$ in fish. almost 1000$. the wrong move may kill everything in your tank. i was just like you. i wanted a marine tank too, but i only had enough for for a freshwater tank. now i have a marine tank and have about 100$ in dead fish. i'm getting better though =) . all i am saying is that marine tanks are VERY expensive. good luck and make the right choice =)