Please help. We live in Florida, which is generally very warm, but we are currently in a cold snap (like the rest of the US). Our house heater decided to stop working last night and the temperature in the house went down to 65 degrees F (thankfully the air stills runs, so it didn't go below that). The tank water (no heater in tank) got down to 67 degrees F. We have a 5 gallon tank. In it, we have 1 male betta, 3 neon tetras, and 1 albino cory catfish. We finally got an A/C technician out this evening and the whole unit needs to be replaced, so we won't have heat again tonight. I'm worried about our fish. My husband replaced 2 quarts of the tank water with warm water about 30 minutes ago and brought the temperature up to 70 degrees F, but I know that won't last long. Is there any way we can keep our fish from freezing? How do we keep the tank warm with no heaters? Suggestions?