yeah my cteno is pretty shy (exept when i have food) they stay in the middle of the tank but mine has his corner on the bottom behind a large sword plant and rarely deviates from there. except to the filter intake, i don't know why but he lets the filter hold him up. they are labrynth fish so they come up and down from wher ever they sit in the tank to the surface, so you might have to watch them with the gars untill he gets bigger. but other than that they're just a normal fish!
good luck with your tank!