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Tetra

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

  • Based on 16,369 reviews
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Availability: In Stock.
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Arrives Wednesday, Dec 17
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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.

Is Discontinued By Manufacturer ‏ : ‎ No


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: #3,995 in Pet Supplies (See Top 100 in Pet Supplies) #11 in Aquarium Heaters


#11 in Aquarium Heaters:


Item Weight: 5.6 ounces


Department: Unisex-Adult


Manufacturer: Tetra


Item model number: 26446


Batteries: Product Specific batteries required.


Date First Available: March 22, 2007


Item Package Dimensions L x W x H: 7.24 x 3.35 x 1.97 inches


Item Dimensions LxWxH: 1.63 x 3.5 x 8.25 inches


Brand Name: Tetra


Target Audience Keyword: fish


Directions: See instructions


Warranty Description: See label


Model Name: Submersible Aquarium Heater


Color: Black


Size: 10-30 Gallon


Material: Plastic & steel


Age Range Description: All Life Stages


Number of Items: 1


Style: 10-30 Gallon


Included Components: Aquaria 75026446 Tetra Submersible Aquarium Heater 100Wt


Specific Uses for Product: Indoor


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Wednesday, Dec 17

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 Heater for smaller aquariums
Size: 2-10 Gallon
Review Image by Josh R Josh R
I’m using the Tetra HT 50-watt heater in a 5-gallon tank, and it’s been excellent so far. The built-in thermostat keeps the water right around 78°F, and the temperature stays steady day and night without needing to adjust anything. I checked it against a thermometer and it’s always within about a degree. Installation was easy — just stick it to the glass with the suction cups and plug it in. The size is perfect for a small tank; it tucks neatly behind a plant and doesn’t get in the way. The indicator light is a nice touch so you know when it’s heating. For a small setup like a 5-gallon betta or shrimp tank, this heater is exactly what you need: simple, quiet, and dependable. Great value for the price. ... show more
Reviewed in the United States on October 24, 2025 by Josh R Josh R
    • Great little heaters
Size: 10-30 Gallon
Easy and uncomplicated, just the way I like it. Either as a standalone heater as in my 30 gallon tank or working in tandem on a thermostat as in my 55 gallon tank they are just dependable inexpensive heaters. I don't know how old my last one was before I replaced it but it had been used for a while before it came to me with the tank I bought and I was so impressed with it's dependability I replaced it with another. Funny thing is it never did fail, I was just being proactive as I didn't know it's age. These are my heaters now. I will say I did take the old suction cup and added it to the new heater. It would be nice if they came with two suction cups. ... show more
Reviewed in the United States on November 2, 2025 by Josh
    • A++ Submersible Heater
Size: 10-30 Gallon
This aquarium heater works perfectly in my 29 gallon aquarium. Initially, I had some doubts due to the inexpensive cost of the heater, but I thought I would give it a try and I’m very happy it works so well. I also like the red light to know it’s heating and then it switches to the green light to let me know the temperature is good, when it takes a rest. I placed this submersible heater horizontally near the bottom of the aquarium per the instructions! ... show more
Reviewed in the United States on October 17, 2025 by KensingtonMike
    • 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
    • Low maintenance and works!
Size: 2-10 Gallon
Short enough to fit in my 5 gallon tank. Keeps it around 76°F. Seems to be low maintenance. Price point is good. My betta enjoys hanging around it. When you first plug it in, the light is red until it reaches the desired temperature point.
Reviewed in the United States on October 27, 2025 by Mom of 7!
    • Great heater for saltwater or freshwater aquariums
Size: 2-10 Gallon
Many people that are rating this product with a 1 or 2 star clearly are not using it right, saying it is going out or not heating hot enough. To use this heater properly, you must sit the heater in the aquarium water for 30 minutes before even plugging it in. This is to set the thermostat inside the heater. Also, you must place the heater set up 90 degrees or laying flat parallel with the bottom of the tank. Another reason it may stop working is, once you turn off the heater you must leave it in the water for 15 minutes before taking it out. Bottom line is, this is a great heater. I use 3 of them total, one for a 10 gallon saltwater nano reef, one for a 10 gallon freshwater aquarium, and one to heat up my water change water. This is one of the best compact heaters I have used, compared to two other more expensive heaters. This is also definitely the cheapest place to find the heater (on amazon), in my local fish stores it runs $17. Ignore the reviews by people that probably didn't even read the instructions before sticking it in their tank and saying it doesn't work right. No adjustments need to be made with this heater and that is one of the greatest things about it also. Pros: Red light when heating Green light when temperature is correct Small and compact Cheap price Good quality Fully Submersible Heats up to 10 gallons Consistent temperature Rubber protects the glass heating tube Cons: Cannot change the temperature if desired. ... show more
Reviewed in the United States on January 12, 2012 by Kameron

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