Thermostat housing removal

Im trying to change my thermostat in my 1990 toronado trofeo....Ive taken the upper hose off and removed the one bolt that is in the housing,But I cant seem to get it to come off,does it twist off,pop off,or how does that exactly come off anyone......If someone can help me i would really appreciate it!!

Twist and pry upward. They get sticky. (Mine did!)