He wasn't moving when I introduced him to the tank, and sat still on the bottom. Didn't eat either, but I figure it's because he's adjusting to the new tank. Tail is also clamped.
The hoplo is now in a 10g quarantine tank with a heater and powerhead for water circulation.
Here's a few pics of the hoplo from yesterday. Notice the areas circled in red. He also has a few tiny growths of columnaris(?) on the top/right area of his head.
Update: the growths seem to have gone away, but he is still sitting in a corner of the QT tank, not moving much unless the current pushes him around. Also fed him some frozen brine shrimp, which he ate reluctantly.



Here's a vid of him this morning with light on.
https://www.youtube.com/watch?v=Knn29Av5rFw