Is it a planted tank? if you are looking to add plants then i would suggest you get them now. IF you are not getting plants, then get a danio. I've always started my cycles w/ them and non of them have died or had health issues until one of my angels snacked on one ^^. If you are looking for fish-less cycling, instead of messing w/ all the chemicals, just put some food in the water and let it rot. (w/ filter on of course). once it clears, get some danios. I wouldn't bother though since danios can def stand the cycling period. (provide u do some partial water changes) How big is the tank anyways? The reason why you should get plants now instead of later is that it does remove some the ammonia/nitrate/nitrite from the water. And since plants do starve the bacteria, the bacteria level wont get as high as a non plant tank, but if u are planning to add plants later, then there is no point in going through the big cycle. you should add 3-4 inch of fish for cycling so that enough bacteria grows to carry heavier loads, otherwise, if you don't get enough in the beginning, u might have some spikes later down the road when u add bigger/more fish. (read up on how much you should start off with cause I'm a bit rusty on that) However, if you have plants then don't worry about it too much. (Warning! Plants are great! but work only if they are growing and not rotting in your water. u need good/enough lighting for the plant, CO2 injection (there are DIY yeast co2 generators w/ yeast/pop can/sugar), and a good substrate w/ good ion exchange rate.) So if you have plants then get a little more fish (4 danios?). ANYONE! CORRECT ME IF I'M WRONG but it has worked for me. I just don't want to give bad info^^