Royal Gramma swimming very strange

[Mcgeezer]

I'm a fairly experienced reef keeper, but I've never had one of these fish until today....the fish is very healthy and eating right away + it was swimming & acting perfectly normal at the store (World Wide Corals)

But now that it's home, it will do nothing but swim sideways or vertically. At first glance, the swimming makes me believe that something is wrong....even though there doesn't appear to be anything wrong at all.

It's my understanding that they swim upside down at night....but is this other behavior considered normal????

 

[Michael Hoaster]

Royal Grammas prefer vertical walls as habitat, so maybe that explains it. Try providing some vertical rock structure, if you don't already have that in the tank. I kept a harem of 7 grammas in a 180 with a built-for-them fake wall which had numerous 'gramma caves' in it. They would surf the currents along the wall, which sounds kinda like what you're describing. They orient their bodies parallel to whatever surface they are near, so they could be vertical or even upside down. Could that be what is happening?