so yea as i ws saying, add what ever substrate you like, gravel, bare bottom tank, sand anything like that, just a word of advice, dont get bright coloured gravel like rainbow mix and stuff, the other members will constantly tell you to change it, they dont like it but its YOUR tank not thiers, so all in all its what you decide to put in,
for hiding and decor, you can choose anything from bogwood, slate, stone, big rocks, flat rocks, cobbles, plastic plants, silk plants, REAL plants, plastic castle LOL anything you want really, though what is best and to observe the fish wit hall its instincts going at full throttle, build an as natural looking setup as possible, such as dark or natural gravel, with some bogwood and some "caves" made from rocks piled on each other / propped up on bog wood, or you can buy fake caves made from fire glass or non toxic plastic from any reputable LFS, if you use rocks out of your garden be careful and thoroughly clean them, soak them in boiling water to get rid of any potential pathogens and or germs / bacteria. then after the cycle, when you get your danios / minnows you could add some real life plants if you wanted, elodia crispa i would reccomend for a first setup, as it is hardy and i have found from personal experience that i can grow in tropical and cold temps.
hope this bit more info is any help
