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Tetra

Tetra 26446 HT Submersible Aquarium Heater With Electronic Thermostat, 100-Watt, Multicolor, 10-30 Gallon

  • Based on 16,781 reviews
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Availability: In Stock.
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Arrives Thursday, Aug 27
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Size: 10-30 Gallon


Features

  • AQUARIUM HEATER: Submersible heater is designed to keep your aquarium at the optimum temperature.
  • AUTOMATIC THERMOSTAT: Electronic thermostat keeps water at a consistent 78 degrees.
  • INDICATOR LIGHT: The red light shows when water is heating; green indicates that the heater is on standby.
  • EASY TO USE: Just attach to an aquarium wall the suction cup securely attaches heater to tank.
  • SIZE: Use this 100-watt heater for 10 to 30 gallon aquariums UL Listed.

Description

Tetra® HT Submersible Heater is designed to keep your aquatic fish comfortable, with an electronic thermostat that automatically maintains a consistent water temperature of 78 degrees and prevents overheating, extending heater life. An indicator light lets you know when the water is heating (red light) and when it reaches the proper temperature (green light). Inside, silicon carbide crystals improve heat distribution and transfer. The strong glass tube is heat and shock resistant. This submersible heater is easy to use – just attach to the inside of the aquarium wall using the suction cup (included) in an area with good water circulation. The Tetra HT Submersible Heater is available in different wattages to fit your aquarium: use the 50-watt HT10 in 2 to 10 gallon aquariums; 100-watt HT30 for 10 to 30 gallons; 150-watt HT40 for 30 to 40 gallons; and 200-watt HT55 for 40 to 55 gallons. This heater is UL Listed. Since 1951, Tetra has developed the world’s most comprehensive body of fish food knowledge, and fishkeeping enthusiasts have looked to the brand for products and solutions that add ease and beauty to their home. Whether you're an experienced hobbyist or just starting out, Tetra has everything you need – from a large variety of quality fish food and innovative equipment to test kits and decor.

Material: Alloy Steel, Plastic


Brand: Tetra


Color: Black


Wattage: 100 watts


Item Weight: 5.6 ounces


Product Dimensions ‏ : ‎ 1.63 x 3.5 x 8.25 inches; 5.6 ounces


Item model number ‏ : ‎ 26446


Department ‏ : ‎ Unisex-Adult


Batteries ‏ : ‎ Product Specific batteries required.


Date First Available ‏ : ‎ March 22, 2007


Manufacturer ‏ : ‎ Tetra


Best Sellers Rank: #9,692 in Pet Supplies (See Top 100 in Pet Supplies) #15 in Aquarium Heaters


#15 in Aquarium Heaters:


Customer Reviews: 4.4 4.4 out of 5 stars (16,781)


Brand Name: Tetra


UPC: 046798264460


Global Trade Identification Number: 60


Warranty Description: See label


Unit Count: 1 Count


Manufacturer: Tetra


Included Components: Aquaria 75026446 Tetra Submersible Aquarium Heater 100Wt


Item Type Name: Aquarium Heater


Model Number: 26446


Part Number: AQ-26446


Material Type: Alloy Steel, Plastic


Color: Black


Wattage: 100 watts


Item Weight: 5.6 ounces


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Thursday, Aug 27

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Similar Products

Top Amazon Reviews

    • Great if you're looking for a basic, no frills and are not concerned about accuracy.
Size: 10-30 Gallon
If your criteria is cheap, "brand name", no frills heater and you don't require the temperature to be a precise OR adjustable temperature, this is perfect for you. It works just well enough and is cheap enough generally get 2 for the price of 1 adjustable heater. For an ambient house of around 70 degrees, it flicks from red (heating) to green (maintaining temp) at 77.1 degrees (not 78). It advertises 78 +- 2 degrees so it's perfectly in line with what you should expect. If you're in need of a precise 78-80 degree heater, look elsewhere. ... show more
Reviewed in the United States on July 12, 2026 by Amazon Customer
    • Great price, fast delivery.
Size: 10-30 Gallon
★★★★★ Great Product! I'm very happy with this purchase. The product arrived on time, was exactly as described, and met my expectations. The quality is excellent, it's easy to use, and it works as intended. I appreciate the value for the price and would definitely purchase it again. I highly recommend this product to anyone looking for a reliable and well-made item. ... show more
Reviewed in the United States on July 1, 2026 by sucketta bryce
    • Proven leader in fish tank equipment
Size: 10-30 Gallon
Established expert in aquarium equipment at affordable prices for sure. The reliability of Tetra items is proven time and again, boosting fish health, tank appearance, and adjustable fit for most tank sizes. About an hour was all that was needed for this to warm a 20 gallon tank, and very accurate even when measured. Overall excellent water temperature maintenance for sensitive live bearing fish. ... show more
Reviewed in the United States on June 12, 2026 by rebelyell80
    • Update: Broken after 2.5 years and Tetra still honored warranty
Size: 2-10 Gallon
Update 01/19/2018: I contacted Tetra for troubleshooting. Although the warranty says 2 years and my broken heater was purchased 2 years and 6 month ago, they still honored the warranty and sent me another one. Because of their awesome customer service I moved the star from 2 to 4. Update 01/13/2018: After a little over 2 years, I found that my 5 gallon aquarium water was evaporating real quick. (1/4 water was gone in 7 days.) I did a quick check and found out the water was 92 degrees Fahrenheit! And still the water heater was "red" (meaning it was still heating up my tank. Thankfully none of my fish were dead as I quickly unplugged the heater and inspected it and I cleaned the outside of the heater thinking that there was a buildup near the sensor. I plugged it back in after a water change which lowered the water temperature back down. After 3 hours of continual heating my aquarium is once again around 83 degrees. The sensor seems to be broken. Barely lasted over 2 years. All I did was plug it in. I have heaters that lasted over a decade. This is unacceptable in my standards. Never again am I buying tetra products for my aquarium needs. Original purchased 05/24/2015 When I got this item, I put it in the aquarium horizontally and left it in the tank for about 6 hours so that the water temperature will match the inner core of the heater's internal thermometer. And then I plugged it in with my fish in the tank although the manual said not to put fish in until after 24 hours have passed and the temperature is steady. I kept an eye on the temperature for about the first 12 hours. The room temperature was around 65 degrees the moment I plugged in and it rose to 80 and the air conditioning kicked in lowering the room temperature. This heater kept my aquarium consistent 78 until the room temperature got 80 which raised my aquarium to 79 degrees and when the AC kicked in it kept the water at 78 degrees. It has been 2 weeks since I had this and I have no issue for my 5 gallon aquarium. Good value for the money. 5 stars ... show more
Reviewed in the United States on June 16, 2015 by Honesty Best Policy
    • Follow instructions
Size: 2-10 Gallon
This is not to be used in a small bowl. Please listen to what the instructions say. It did not work out for me at all but it was user error. The product itself worked fine.
Reviewed in the United States on June 28, 2026 by Embo
    • Quit fighting adjustable heaters, solution for Fluval Spec
Size: 2-10 Gallon
I’ve recently been down a long road with aquarium heaters. First off, I have a Fluval Spec III. This tank will accommodate a heater in the rear pump section. As far as I know, there are only 3 commonly available adjustable heaters that will fit. The Hydor Theo 25W, the Marina 25W, and the Aqueon Pro 50W. I’m now on my 4th Hydor Theo in less than 6 months. These seem to fail and overheat in a matter of weeks to months. I tried the Marina, it simply didn’t get up to the 78 degree F required for most tropical fish. Last, I was turned off by the Aqueon Pro as for the price it should have better reviews. It appears all these heaters have gone downhill in recent years. I went back to researching to see if there was another option. That led me to this. I was reluctant to try it, as it’s not adjustable, but it claims to be thermostat controlled at a preset 78 degrees F. Being out of options, I figured it can’t hurt to try... Oh my! I am so pleased to not be fiddling around with thermostats anymore. This works beautifully, is very compact, and it easily fits in the rear pump section of my Spec tank. The package does claim to have a variance of + or - 2 degrees F, but I’ve noticed it maintaining 77-78 quite consistently. If you’ve been fighting the adjustable heaters like I have, this is the solution for you. ... show more
Reviewed in the United States on August 19, 2020 by The Isaacsons
    • Worked for 2 weeks!!!
Size: 2-10 Gallon
Got this 2 weeks ago and was thrilled that it kept my 3 gallon tank warm and my betta happy... until it stopped working last night after I cleaned the tank and changed partial water. It stopped working all together and water is ICE COLD this morning! The light is green and will occasionally turn red for a few seconds before going back to green (which is supposed to indicate the the water is at the correct temperature). Still cold. I called Tetra customer service after reading many of the reviews here with the same issue. I explained what happened and asked if there is anything I could do to fix it or reset the heater as another reviewer mentioned that customer service gave instructions which fixed the issue. The customer service rep I spoke to would not help or even talk to me further if I could not tell him the temperature. I explained that I do not have a thermostat therefore I wouldn't be able to check the temp but I assured him that the water was noticeably cold to touch in comparison to the warm water that has been consistent in the tank in the 2 weeks I've had this heater and tank. He rudely continued to cut me off and said that he couldn't help me if I don't have a temperature and he became more and more condescending in his tone has he continued. His customer service was TERRIBLE! I told him that I understood he needed to know the actual temp and that he couldn't trust the temperature based on touch, so I asked if he could at least tell me what the possible options are as far as fixing this issue would be as I saw many other amazon reviewers shared the same issue. He became increasingly frustrated, increasingly rude, saying that he needs the temperature to know if he needs to send a replacement etc. I graciously explained that it was not my intention to get a replacement. I just wanted to know if he could help me troubleshoot so that I can attempt to fix my heater before my betta dies. I'm not interested in waiting for a replacement heater to come in the mail. Eventually I just asked to speak to his supervisor multiple times before he finally he basically said (like a child with a bad attitude) "Fine....." and he patched me directly through to someone's voicemail. I WILL NEVER PURCHASE TETRA PRODUCTS for the simple fact that customer service is NOT a priority to them. A simple "I'm sorry you're having trouble with your new heater. Tell me what's happening and let's see what we can do...." would have been great and I would be willing to go to the nearest pet store and buy a replacement myself if he was willing to help me troubleshoot and exhaust all options first. Instead, the gentleman has no customer service training, does not know the meaning of showing empathy, and is not interested in helping anyone... unless you can tell him the temperature of the water even though this heater doesn't have a thermostat in the first place. ... show more
Reviewed in the United States on October 7, 2020 by L
    • Reliable
Size: 2-10 Gallon
Works great. Durable. We live in Florida and she to the weather or power goes out a lot. Still working with all the surges.
Reviewed in the United States on July 1, 2026 by Tara Underwood Burnett

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