Can You Heat A Small Tank?

lynn.12

Member
Hey everyone,

Thanks for maintaining a forum for beginner help requests, much appreciated!!

Anyways, I have a betta in a 5 gallon tank and no other fish. Tank is filtered but not heated and water is remineralized RO. I’ve had this going about 6 months but much of that was summer and we don’t use AC. I live in southern california so the winter isn’t very brutal, but it’s definitely been rather cold some recent mornings and I’m realizing the betta would likely appreciate some warmth. So far he remains very hungry and active but I ordered a Tetra HT20 50W heater with the intention of adding it to my setup. However in the meantime I’ve come across some horror stories online of people cooking their fish by trying to heat small setups..

So my question is, is it worth heating the tank, or will I risk stressing him out more with temperature spikes?

Any insight appreciated. Thank you!!
 

AquaticJ

Member
Unless his tank is consistently 78-80 degrees, you need a heater. For every horror story there’s thousands of happy fish. Heaters can cook even big tanks.
 
  • Thread Starter

lynn.12

Member
Ok thanks, tank is definitely not that warm right now.. I’ll add the heater but do I need to be concerned about stressing him out as I bring up the temp?

note— I picked the heater out because of good reviews but also it only controls to 78 degrees, I can’t work up the temp gradually. Not opposed to getting a different one though if I have to.

I’m about to leave for a week so if this is something potentially very stressful I may push it til I get back
 

FlipFlopFishFlake

Member
The temp should gradually raise as the heater increases the water temperature, your betta should be fine.
 

FiscCyning

Member
Ideally you would raise the temp slowly over several hours. Does that heater let you adjust the temp or is it preset?

Edit: just saw you posted while I was typing. Even without an adjustable dial, you should be fine. It will still take the heater some time to get the water up to 78.
 
  • Thread Starter

lynn.12

Member
Ok awesome. Thanks so much for all the quick feedback. In retrospect it’s a little idiotic that I’d be more scared of temp fluctuation or heater malfunction than I would be of maintaining water at a totally unhealthy temperature.. but luckily he’s a trooper so far and I’ll get that heater in tomorrow
 

AquaticJ

Member
A 50 watt heater that’s preset will probably make it too hot honestly. There are many factors but I’d recommend an adjustable one. A 50 watt heater won’t take more than a few hours to ramp up the heat in a 5 gallon.
 
  • Thread Starter

lynn.12

Member
Any recommendations on type then? I can monitor the thermometer for a couple days if this is like kinda a worry, but if it’s a major worry i’ll just get a new one
 

Wraithen

Member
AquaticJ said:
A 50 watt heater that’s preset will probably make it too hot honestly. There are many factors but I’d recommend an adjustable one. A 50 watt heater won’t take more than a few hours to ramp up the heat in a 5 gallon.
Is that first statement based on anything? Ive used 50 watt heater and they turn off when the water contacting them reached 77.8 degrees. How would the heater overheat the tank when it shuts itself off at its preset temp?
 

VSA

Member
lynn.12 said:
Any recommendations on type then? I can monitor the thermometer for a couple days if this is like kinda a worry, but if it’s a major worry i’ll just get a new one
I have been using one of these:

Was more expensive then the rest but has a wide range of settings and is easy to hide. Has been reliable for me since I got it in October.
 

SuperMon

Member
Not to scare you, but I had that heater at one point and it exploded . . .at the very least the clear part broke apart in my tank, but no fish causalities. I just vacuumed the shards and upgraded brands. If I remember correctly the heater turns on as needed, once it hits 78 it turns off, turns back on once it drops a few degrees so you're going to have some flux.

Personally if my house temp is 75+ I check the fish tank temp and turn on a heater if needed. Currently my outside is freezing, my house temp is set for 75 and my tank is holding a 79 temp no internal heater, but my tank is near our house heat vent. If the heater still worries you, just move the tank maybe to a warmer room in your house ie. kitchen, living room. So either use the heater sparingly (because I used 50 watts for my 10 gallon when I lived in socal and it took under 2 hours to heat and hold temp for hours after turn off) or keep a warmer house temp
 

Fanatic

Member
HI Lynn12,

You can use a preset heater, but a lot of people prefer to use adjustable because it can heat a wide range of temperature.
My favorite heaters are adjustable, only because it's very easy to use them, and they give a clear warning when they are turning on or off.
 

THRESHER

Member
I got one of these in my 20 gallon with a single Dragon Goby. Keeps the temp between 78-80. Comes on when it needs to and shuts off when temp is reached.
 

AquaticJ

Member
Wraithen said:
Is that first statement based on anything? Ive used 50 watt heater and they turn off when the water contacting them reached 77.8 degrees. How would the heater overheat the tank when it shuts itself off at its preset temp?
A lot of preset heaters are meant for specific volumes of water, so they’re designed to turn off and on a specific amount to treat said volume of water. I’ve tested this with my preset heater in my 55, it gets the 55 to 77, but when I put it in the 10 gallon it went to 83.
 

Wraithen

Member
AquaticJ said:
A lot of preset heaters are meant for specific volumes of water, so they’re designed to turn off and on a specific amount to treat said volume of water. I’ve tested this with my preset heater in my 55, it gets the 55 to 77, but when I put it in the 10 gallon it went to 83.
If that's true its a terrible idea from the manufacturer. How would they know what room the heater is in? They would cook a tank in an 80 degree room and freeze one in a 65 degree room. While I wouldnt doubt a 50w heater being unable to heat a 55 gallon, idk why it would run so hot in a 10. Possible mis calibrated heater?
 

AquaticJ

Member
Wraithen said:
If that's true its a terrible idea from the manufacturer. How would they know what room the heater is in? They would cook a tank in an 80 degree room and freeze one in a 65 degree room. While I wouldnt doubt a 50w heater being unable to heat a 55 gallon, idk why it would run so hot in a 10. Possible mis calibrated heater?
My heater is more than 50w, but I was just giving an example of putting it in a smaller tank. 50w is about double the wattage needed for a 5 gal.
 

Marzahtha

Member
The preset heater will be fine for a Betta. It's preset to 78 degrees. My tank usually sits around 77.8 I use the HT10 in my 5.5 gallon tank where I have guppy fry. It's smaller and fits better.
 

mattgirl

Member
The only tank I use a small preset heater in is my 2.5 gallon snail jar. I don't remember the wattage in it. I bought 2 of them well over 15 years ago. I am thinking they are at least 50 watt though. I do know it wouldn't warm up my 10 gallon tank so I bought a 100 watt adjustable for it.

The 5.5, 10 and 55 all have adjustable heaters. The 5.5 and 10 have 100 watt heaters and the 55 has a 200 watt heater. It gets fairly cool in here at night but the heaters hold the tanks temps right at 76 at all times. i

What ever you do don't just set and forget. I've yet to get a heater that I can rely on the dial. What I do is set the dial just under the temp I want the tank to be. If it turns off before the thermometer tells me the water temp is where I want it I turn it up just a tiny bit. I keep doing this until I am sure it is going to hold the temp I need it to be. I continue checking it against the thermometer over several days.

I also keep a thermometer in the tank at all times and check it often to make sure the heater is doing its job.
 

DarkOne

Member
AquaticJ said:
A lot of preset heaters are meant for specific volumes of water, so they’re designed to turn off and on a specific amount to treat said volume of water. I’ve tested this with my preset heater in my 55, it gets the 55 to 77, but when I put it in the 10 gallon it went to 83.
You had a faulty heater. That is not how heaters work at all. I have a Tetra HT10 preset in a Fluval Spec 3 (2.6g) and it stays at 78°F. I have another HT10 in a 5.5g and it also maintains 78°F.
 

HelloKittyPowa

Member
lynn.12 I have the same exact heater for my 5 gallon as well and I definitely do recommend it. It has the temp adjust to 78 which is perfect for a betta. I had it since October of this year and it works great, it does not overheat. Only advice I would give is... Which I am sure other fish owners do, is unplug it when you are doing water changes. A submersible aquarium heater which you are getting, should always be unplugged when performing a water change for 2 main reasons. First, if you leave your heater on and expose it to air, it can overheat. Secondly, when the hot glass comes back into contact with cool water, the heater may crack from the sudden temperature change.
 

mattgirl

Member
AquaticJ said:
A lot of preset heaters are meant for specific volumes of water, so they’re designed to turn off and on a specific amount to treat said volume of water. I’ve tested this with my preset heater in my 55, it gets the 55 to 77, but when I put it in the 10 gallon it went to 83.
I agree that they are meant for a specific amount of water. That actually tells me that the heater was set to turn off at 83 but was too small to heat 55 gallons of water up to its limit.

The preset heater I have in my snail jar heats the water up to 76 but when I had it in my 10 gallon it only heated it up to 72. The heater couldn't heat that volume of water up to its preset limit.

If the OP does decide to use the preset heater she bought it would be best to make sure it won't over heat her small tank. It just depends what temp it is preset at.
 

Wraithen

Member
mattgirl said:
The only tank I use a small preset heater in is my 2.5 gallon snail jar. I don't remember the wattage in it. I bought 2 of them well over 15 years ago. I am thinking they are at least 50 watt though. I do know it wouldn't warm up my 10 gallon tank so I bought a 100 watt adjustable for it.

The 5.5, 10 and 55 all have adjustable heaters. The 5.5 and 10 have 100 watt heaters and the 55 has a 200 watt heater. It gets fairly cool in here at night but the heaters hold the tanks temps right at 76 at all times. i

What ever you do don't just set and forget. I've yet to get a heater that I can rely on the dial. What I do is set the dial just under the temp I want the tank to be. If it turns off before the thermometer tells me the water temp is where I want it I turn it up just a tiny bit. I keep doing this until I am sure it is going to hold the temp I need it to be. I continue checking it against the thermometer over several days.

I also keep a thermometer in the tank at all times and check it often to make sure the heater is doing its job.
Ive got 2 or 3 heaters that use a led readout for set temp and current temp. They are all within .2 degrees of each other and my thermometer.
 

mattgirl

Member
Wraithen said:
Ive got 2 or 3 heaters that use a led readout for set temp and current temp. They are all within .2 degrees of each other and my thermometer.
I have 3 heaters with the led lights to tell me when they are off and on. I can't depend on the dial on any of the 3. One of them has to be set at 73 to keep a steady 76. The other 2 aren't as far off but neither of them are set at 76. That is what I maintain all of my tanks at.
 

Wraithen

Member
mattgirl said:
I have 3 heaters with the led lights to tell me when they are off and on. I can't depend on the dial on any of the 3. One of them has to be set at 73 to keep a steady 76. The other 2 aren't as far off but neither of them are set at 76. That is what I maintain all of my tanks at.
That's why I specified readouts, not lights. The one I have with just a knob to set the temp is wrong, but I suspect the problem being with the setting knob, not the internal thermostat.
 

AquaticJ

Member
Out of my 12 tanks, mostly adjustable heaters with the appropriate wattage per tank, most of them are not set to the temperature the tank is actually at. There’s so many factors to the actual aquarium temperature. Including but not limited to room temperature, tightness or lack of aquarium hood, internal or external filters (surprise, your filters add heat), lights, etc. I’ve had several preset heaters that also didn’t get it to the correct temperature.
 

mattgirl

Member
AquaticJ said:
Out of my 12 tanks, mostly adjustable heaters with the appropriate wattage per tank, most of them are not set to the temperature the tank is actually at. There’s so many factors to the actual aquarium temperature. Including but not limited to room temperature, tightness or lack of aquarium hood, internal or external filters (surprise, your filters add heat), lights, etc. I’ve had several preset heaters that also didn’t get it to the correct temperature.
And this is why a dependable thermometer is not just a luxury but is a necessity. I actually have 2 thermometers on each of my tanks. As long as both are reading the same I am assured that my heaters are set at the right temp. I depend on the thermometers, never on the dial.
 
  • Thread Starter

lynn.12

Member
I think I said HT20 but it’s actually HT10. Anyways I’m trying it out now but will continue to monitor for a few hours after it hits its set point to ensure it doesn’t go over.. any issues and I’ll go get a non preset one.

I was going to consider waiting til I get a non preset one before doing anything but then I came home today and it was freezing so I opted to not test his cold tolerance any further..
 
  • Thread Starter

lynn.12

Member
so just an update, I’m sure this will surprise no one but he does seem to like the heat—he built an impressive bubble nest today and I haven’t seen one of those for a couple months so that’s probably not a coincidence! the heater is successfully maintaining a steady 78. thanks all for you help!
 

imba

Member
Y
AquaticJ said:
A lot of preset heaters are meant for specific volumes of water, so they’re designed to turn off and on a specific amount to treat said volume of water. I’ve tested this with my preset heater in my 55, it gets the 55 to 77, but when I put it in the 10 gallon it went to 83.
It is highly likely that the heather is faulty. Preset or adjustable, the heater should turn off once the temperature reaches the required/desired temperature
 

JB92668

I use a 15 wat heater to heat my 20 liter tank and no fish have been cooked
 

Most photos, videos and links are disabled if you are not logged in.

Log in or register to view

Top Bottom