Adding Sand to Existing Tank

[Tarobot]

I've got a barebottom 15g with 10 black neon tetras, cherry shrimps, drift wood, hornworts and java fern and i was thinking about adding in black sand so it's not barebottom anymore, is it highly recommended to take everything (including water) out to add 3m black sand or is it ok if i somehow slowly add it in cup by cup?

and also which kind of fine black sand do you guys recommend and where to get it ?

[target]

As long as you have rinsed the sand sand well you shouldn't have a problem adding it cup by cup. For me I would take all the fish out, drain the tank, add the sand all at once. It's what I did on my 46g when I had it. On your 15g it shouldn't take too much time at all.

[gklaw]

For a 15g, it is probably much faster to take all the livestock and water out. Lay the sand on the bottom. Put plate or glass in sand and add water back. May be a good time to do a WC in the process as well