Agreed w/ both comments above. Water stability, and not changing flow or lighting will aid in it finding a “comfortable” place… for a short period of time. More than likely, this guy has settled at the bottom Bc it’s acclimating to your lights. BTA’s aren’t to keen on dwelling near the substrate. They like rock work. Once it gets acclimated to those, it’ll more than likely make it’s way up the rock towards them. Nems move… BTA’s especially… And there’s not really much you can do about it, unfortunately. It can be in the same place for months. Then you go to bed one night only to wake up to it in the completely opposite side of the tank, or worse, caught in your intake/power heads. Only thing you can do is watch it closely, and be prepared to move something on a whim if needed