This morning I noticed the thermometer in my betta's 5 gallon tank read 90 degrees fahrenheit when it should've been at 80 degrees. He seemed a little stressed, but he seemed fine. I immediately unplugged the heater (a 25w Hydor that's been working perfectly for 9 months) and let the tank cool to 80 degrees, which took about 4 hours. After that, I plugged the heater back in and turned the dial from 79 to 75, but noticed over the course of an hour and a half, the on/off light never shut off (like it should). I messed around with the dial and turned it all the way down to see if it would ever shut off. I unplugged it and plugged it back in hoping to "reset" it, but the light never came on. I turned it up to see if it would turn on, but it didn't. I think by messing around with the heater I've officially broke it, so I went ahead and removed it from the tank. Now, the questions are: Will my betta be okay for a week without a heater (for the time it takes to order a new one)? The temperature of my house is 70 degrees fahrenheit. Also, will he be okay with all this change in temperature? As of right now, he's still active and "begging" for food. The temperature right now is 78, but I know it will cool down more overnight. Another question; what heater do you recommend for a 5 gallon that I can buy off of Amazon for a low price?