I disagree, kuhlis, especially newly purchased, can be quite sensitive to new parameters. I drip acclimate mine, so they are exposed very gradually to the new water.
I had one batch of them, from a local store, where 90% of them died within a week of getting them. This place has a 5 day replacement guarantee, and they did replace them, twice, until I decided it was just a bad batch and took credit instead. Sometimes they are just poorly handled in shipment or poorly acclimated in store, and that can lead to deaths, and if you buy them very soon after they arrive, it's more stress on them with two adjustments in a short space of time. All the scaleless or very finely scaled fish are more sensitive than fish with the more usual scales are.
I find they do best in large groups, I keep at least a dozen together if at all possible. Black ones and the striped ones get on fine and while they don't really hang out together they will snuggle under rocks or wood together, and that's what they like.
They also have a habit of squeezing themselves into the tiniest of cracks and can damage themselves doing so. Don't have coarse or rough rocks in their tank, or coarse gravel. But you'd see scrapes or wounds if they'd gotten into a tight spot. I had one that showed up one day missing scales on half of one side. He died the next day. Still don't know what he got into, but two that got into the filter are fine and were not hurt at all.
If you can I'd get at least two more, six is the fewest I would keep in one tank. They also need places to hide. Rock or wood that they can get underneath. Or lots of plants. The more hiding places, the bolder they tend to be once they get used to a new tank.
that's the water test right after I found him.
