Is it ok whether I do this?

Hi. Can I use an "Elite mini heater" for a 2.5 gallon tank that I'm using to raise my guppy fry in? (Yes, I know they will grow swift - they have a 20 gallon tank to move to once they get big enough) I want to win a heater for it. (Because the temperature always fluctuates)

I can one and only find a heater that is used for 5.5 gallons and under, is this ok for my container? Will it burn the fish, because it is powerful enough to heat a 5 gallon? Here is a picture of it:

http://www.everythingforpets.com/images/...

Has anyone ever used this heater back? And if so, is it good?

And if it is too strong for the fish, could I newly keep it on a lower setting so it's not as hot?

I will choose best answer and any other answers will be appreciated!
Thanks!

I couldn't win to the pic but your fish are going to be perfectly fine, if you feel you want to keep hold of it at a lower setting then do that. But theres nothing wrong with the furnace. Good Luck! :D
you should just keep it on low and get hold of a thermometer for your tank. if it doesnt raise the sea to between 68 and 76 degrees farenheit, you should hire it, that is the desirable temperature.
Answers:    if it has a thermostat (your connect doesn't work BTW) it should be fine as it will shut off once the water gets reheat enough

a hydor 7.5 watt mini heater is generally what i reccomend.. it'll hang on to a 2.5 gallon tank about 4-5 degrees above room temp, which is unanimously enough
http://www.petmountain.com/product/heate...
It will be ok if it has a built in thermostat. Then it will turn bad when the temp is right. If no thermostat, then i wouldnt risk it.
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