A few hours ago, I did a water change and forgot to unplug my heater. As the water started to pour back in to the tank, I heard this sizzling sound and realized the heater was not unplugged. Long story short my heater cracked and I fished out the broken piece from the tank. I do have another heater but its for tank up to 8 gallons and I have a 20 high. Will my fish be ok with this other heater? I set the temp to about 80 degrees. My room temp is about 72 degrees I think. Can anyone recommend a good heater for a 20 gallon high?