Are you thinking of shellies then? If so, aragonite (sand or very small grain) is ideal because they like to dig. N. brevis are pair forming and share a shell (you need shells - escargot shells from gourmet grocers work great) - 2-3 pairs would be max for the tank and you could have some hard water happy schooling fish up top, N. multifasciatus are colony forming and hard to tell apart, but luckily they like each other if from the same dealers tank - so try and get the largest two plus four small ones (likely 2 males and a female) but no up top tankmates - they attack other fish in waves (so, they're not just bulldozers with fins, but mean bulldozers with fins...they'll bite your fingers, or at least try to since they're only 1.5", long when you clean the tank). Brevis tend to mostly leave plants alone, multis will dig up anything and arrange it to their liking (they're bulldozers with fins - you can wake up after smoothing up the gravel to find all of it shoved off to one side of the tank).
If you're thinking of the SA fish or African riverine I listed...they'll be happier with all your plants.
Eric