# Can I use a heater designated for a larger tank in a small tank?



## skincareaddicted

Another betta of mine is sick. I think he has been sick since I bought him. I thought he was lively always swimming vigorously. I didn't realize the white spots on his head was itchy until he started rubbing his head in the gravel  . He was in a gallon container but I am moving him to a 2.5 gallon tank my African dwarf frogs were in.

I just purchased a Neptune submersible aquarium heater 50 Watt which is recommended for a ten gallon tank. The 25 watt was recommended for a 5 gallon but I decided to go with the 50 watt. I was about to buy a new 10 gallon to put my betta in but I have no space left in my room for another tank. My question is would it be ok to use the 50 watt heater in a 2.5 gallon tank? or should I just try clear room out for a 10 gallon? 

Thanks! Kristen~


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## cwlodarczyk

If you really want to keep the small tank for now you can find low wattage preset heaters designed for tanks under 5G. The major chain pet stores should carry them, and I know that Wal Mart has them for sure.

I wouldn't suggest using a 50W heater in that tank - you might end up with soup.


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## Raul-7

skincareaddicted said:


> Another betta of mine is sick. I think he has been sick since i bought him. I thought he was lively always swimming vigorously :bathbaby: . I didn't realize the white spots on his head was ich until he started rubbing his head in the gravel  . He was in a gallon container but I am moving him to a 2.5 gallon tank my african dwarf frogs were in.
> 
> I just purchased a Neptune submersible aquarium heater 50 Watt which is recommended for a ten gallon tank. The 25 watt was recommended for a 5 gallon but i decided to go with the 50 watt. I was about to buy a new 10 gallon to put my betta in but i have no space left in my room for another tank. My question is would it be ok to use the 50 watt heater in a 2.5 gallon tank? or should i just try clear room out for a 10 gallon?
> 
> Thanks! Kristen~


Sure. Most aquarists use heaters that are supposed to be geared towards larger aquariums on smaller sized aquariums to speed up heating and to help keep the temperature constant for longer periods of time. It shouldn't do any harm at all unless you used a heater way out of range like a 500W heater on a 10G. Similarly how most of use larger filters on smaller tanks. HTH.

EDIT: I'd recommend the 50W on the 10G, not the 2.5G. A 50W heater on a 2.5G would heat the water too quickly for the fish's comfort. Sorry, I missed the 2.5G part.


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## skincareaddicted

I read somewhere that heaters for little tanks were bad, so I was afraid the 25 watt would be inadequate. Based on your replies, I think I will swap the 50 watt for thr 25 watt just in case my betta is uncomfortable. Thanks!


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## skincareaddicted

I found this online from aquairumpros.com :

"I have a 20 gallon tank and my friend has kindly given me a a 300 watt heater. Is this too much for my tank?

Actually, there is no harm at all in using a large heater in a small tank. Modern aquarium heaters are equipped with a thermostat which turns the heater on and off when the tank water varies from the desired temperature. Using a large heater will result in the heater coming on less often. That will be the only effect this will have."

What do you all think of that?


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## furballi

A powerful quality heater will work in a smaller tank. Most will require immersion beyond certain level for proper operation. The downside is if the heater doesn't shut-off, then it will fry your fish.

Per my previous post, I think you have a temperature and water quality issue. Use an accurate thermometer to raise the temperature to 85F if you need to cure white spot. Use a bare tank until you get the water quality issue under control. DO NOT OVERFEED. DO NOT let food drop to the bottom. Change 50% of the water each week.


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## simpsota

My big concern would be a malfunction. You could "make soup" as cwlodarczyk suggested in a short period of time if that thing gets stuck in the on position. I'd keep a close eye on it if you're going to use it. That's the main reason why I go with two smaller units on my 50g tank. If one goes hot it won't be enough to fry my fish and if it goes cold the other will keep the temp from dropping too much.

I've used a 25w on my 2.5g for 2 years now and it works fine. Just make sure you've got reasonable flow near it and you'll be fine.


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## furballi

Have an old Ebo 75 watter in a 50 gal. Room temperature can drop as low as 60F. The regulated temperature is 75F, plus/minus 0.5F during the winter. The tank can hit 70F during the summer (no heat).

If your house is always above 70F, then there is no need for a heater. Avoid placing the tank near windows or A/C.

I saw a quality red crowntail betta @ Petsmart in Huntington Beach last week. Again, good specimens are rare, but these guys should recover nicely if given clean water and temperature above 72F. 

Look for good solid colour throughout the body. The fish should be semi-active without any visual damage to body and/or fins. Keep the jar above 75F during transportation to your home.


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## joycould

Wal mart does have heaters for smaller tanks usually they are shorter. If your small tank has a light on it usually that is enough to bring up the temperature a couple of degrees.


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## ihooklow

The problems with larger heaters on small tanks is two-fold.

First, the larger heater generates quite a bit of heat which could cause the temp to go up very quickly - which can be a bit stressful for the fish.

Second, because the larger heater does generate so much heat it cycles on/off much more frequently - which can increase the chances of a malfunction and accelerate the demise of the heater.

That said, most modern heaters are pretty reliable (as long as you stick with the well-established brands) and a 50W shouldn't generate too much heat too quickly for a 2.5-gallon. The 300W in the 20-gallon is far too much, though.

I generally go for two heaters that are both under half the recommended wattage for the tank size. I would rather have a tank a few degrees too cold overnight than overheated and the odds of both failing at the same time are slim-to-none.


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## JG06

If you're only trying to heat 2.5 gallons of water, how about putting a reading lamp over the top of the tank with a 100W incandescent lamp in it? That aught to provide plenty of heat and you probably won't have to buy anything. 

Otherwise, Wally-world and most chain pet stores sell small submersible heaters for turtle terrariums, vivariums, and small aquariums. I would highly recommend one of those over a 50W heater.


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## furballi

I'd go with a 75W unit by Jager ($14). The newer design is just okay. Jager's patented thin wire heating element provides even heat distribution (wire does not glow red). My 2nd choice is the Visi-Therm Stealth 75W. Avoid cheap heaters from Wal-Mart, Petsmart, etc.

The Tronic heaters are very good, but they are very expensive.

http://www.drsfostersmith.com/Produ...ll&Ntx=mode+matchallpartial&Np=1&N=2004&Nty=1

http://www.drsfostersmith.com/produ...&Ntx=mode+matchallpartial&Np=1&pc=1&N=0&Nty=1


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## skincareaddicted

I am not going to use the 50 watt for the 2.5 gallon but found the debate interesting. 

JG06--I am trying to heat the tank up to get rid of ich and I don't think a desk lamp would be able to raise the water to 86 degrees would it? 

I went out and finally found (after going to three stores, a 25 watt heater) and i think it's broken. i am so frustrated.


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## furballi

A 25W heater will also cook the fish if it is stuck open. 75W will do it in 15 min, 25W in 1 hour. Take your poison with that small tank. The best strategy is to buy a *quality* heater that does not apply a lot of current to the Nichrome heating wire.

You can also add salt at a concentration of 1 teaspoon per 1 gal to treat white spot. Maintain this salt level for 7 days. Change 50% of the water. Time is critical to effectively treat white spot. The chance of recovery is less than 75% if you wait more than 24 hour from the first appearance of white spot.


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## skincareaddicted

After reading past posts, I have been salting the tank per proportions recommended. The betta seems to be itching a lot less and I finally found a 25 watt submersible heater at yet another petsmart (marineland neptune submerisble) and the water is warming up nicely. 

I don't know when the white spots appeared, i remember thinking he had something on his head at the LFS but thought it might be his coloring, but your post is scaring me furballi!


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## furballi

Most fish will not make it if you wait 3 days before treating white spot.

You'll need some water circulation to avoid hot spot in the tank when using a heater.


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