I went to Petland this morning and bought a 150w heater and some quick cure for the ICK. I changed 30% of the water before I put the medicine in, along with some slime coat. The temperature is steady at 84 deg. Two fo the dempseys died this morning before I was able to treat. The remaining Dempsey and the the two Green Terrors are now huddled up together in the corner of the tank behind a rock. Looking at them, I cant' see any signs of Ick. They do have 'clamped fins' though. What could be wrong?