Hello, I have a 10 gallon tank with 1 angel fish,1 black skirt tetras and 2 ghost shrimp. I don't have ANY decorations in it. I'm going to get some soon. But i just wanted to know how i should go about putting the decorations in the take? Should i do it when i'm changing 25% of the water, Do i add anything to make it safe for the tank, Do i need to rinse it off before i put it in the tank? I'm just confused with all this stuff. 1 other question...When i change 25% of the water every 2 weeks should i add anything to make the water safe?