Hi, guys, My friend is giving me her old 10 gallon goldfish tank all cycled and everything, but I want to make changes to it. First I'm going to take the goldfish to the lfs Then I am going to take out the turquoise colored gravel and put in some black sand/gravel- will his mean I have to cycle again even if I keep about 4 gallons of the water and the same filter? Then I'm going to put some java in it and get some male endlers and a betta ( would this work?) So would i have to cycle it again- I can keep about 4.8 gallons of water? And the same filter Sry about the formatting I'm on my cellphone. Thanks!