I used tahitian moon sand in my betta tanks a few times. You could see everything that landed on it. In a 3 gallon tank, you could vacuum it up pretty quick but I could see that becoming a problem with more than one critter living in there. then again, i use a really fine white sand in my current reef tank and I see a lot on that, too. I also didn't love the texture. It would always stick to the glass when I was cleaning and was very coarse, but I don't know what brand you're planning to use. good luck choosing!