I can realize you are very new to the hobby. Now is not the time to worry about the nem in question, its time to worry about the tank housing him. The nem can never recover if the tank is not taken care of.
ANY AMMO IS bad, your tank is not cycled. A cycled tank "if it has an ammo spike" will always read nitrItes and nitrAtes. Thats the part of the cycle.
I suggest you give the nem to someone who has an established tank, who can hold it for u until you finish your cycle. And yes throwing 30lbs of dry rock in a 55 will recycle the tank. I could throw 30 into my 120 or 125, and it would read ammo and Ites.
BTA's are super hardy, I've had them live months under cfl's in my fuge(forgot about them/bad fishkeeper). I've given/sold more BTA's then I own, and I own 10+ at a time. If a BTA is dying, its the source(bad bta), or the water. Rarely ever is it the lighting.