Cooking thermometer to measure water temp?

I can't imagine why a cooking thermometer wouldn't work for water, but I'm a little skeptical of the readings I'm getting. I just bought a fish tank and a betta and I'm waiting for the heater to get the water up to temp before I add the fish. So I measured the temp with a digital probe thermometer and it read 95 degrees! Not only does the water feel pretty cool to the touch but the heater is still on and it should turn off once it gets to 76. I'm I missing something here or is my thermometer broken?