HELP osmoregulatory stress

[predatorpassion]

I just purchased an ornate bichir earlier this morning, after it was acclimated and released into the tank. It wouldnt stop bothering my RCK, biting him on the back a few times, etc. I moved the bichir out but the problem now is he is showing symptoms of osmoregulatory stress. Frantic swimming, equilibrium off whack, constant breathing at the surface and what looks to be almost seizures. Hes a healthy fish about 7-10 inches, and the tank parameters all checked out to be fine. Im just aware that stress can cause this. I added some salt to the tank at 1 teaspoon/ 5 gallons. Im not sure what else to do, if someone could please help. Do not want to lose this fish, thank you for your time