How long have you had the tank at your house? For an established tank you shouldn't be seeing any ammonia or nitrite. If you can find out what brand thermometer you had, contact the manufacturer and ask what it is filled with. I think most are completley non-toxic anymore.
If you just moved the tank, I'm guessing something went bad in the move. I recently lost most of my livestock due to a move.
, your 60g is really really really overstocked as stated above. You have more than enough fish to fill both tanks once the 2nd is up and running again.