I've had one of my Rusty's holding position for at least a week now. She used to be pretty active, but then she started hiding under a plant, facing down. She'll stay like that for quite a while, even when other fish swim by. I've been keeping an eye on the tank and I don't think she's being bullied.
My water specs are:
NH3- 0
NO2- 0
NO3- 40
pH- 8.0
Is this normal behavior for a Rusty?