Search  for anything...
DaToo

DaToo Mini Aquarium Heater 25W Small Fish Tank Heater 25 Watt with Free Thermometer Sticker

  • Based on 4,750 reviews
Condition: New
Checking for the best price...
$6.69 Why this price?
Save $3.30 was $9.99

Buy Now, Pay Later

As low as $1 / mo
  • – 4-month term
  • – No impact on credit to apply
  • – Instant approval decision
  • – Secure and straightforward checkout

Ready to go? Add this product to your cart and select a plan during checkout.

Payment plans are offered through our trusted finance partners Klarna, Affirm, Afterpay, Apple Pay, and PayTomorrow. No-credit-needed leasing options through Acima may also be available at checkout.

Learn more about financing & leasing here.

Selected Option

Free shipping on this product

FREE 30-day refund/replacement

To qualify for a full refund, items must be returned in their original, unused condition. If an item is returned in a used, damaged, or materially different state, you may be granted a partial refund.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

Availability: In Stock.
Fulfilled by Amazon
Arrives Tuesday, Jun 9
Order within 20 hours and 51 minutes
Available payment plans shown during checkout
Protection Plan Protect Your Purchase
Checking for protection plans...

Recently Viewed

Size: 25W


Features

  • 25W Betta Aquarium Heater: Creating and maintaining a perfect and comfortable water temperature for our cute fish is not easy, which requires a lot of effort. Now DaToo MINI 25W Aquarium Heater can help you make this easier. Precise and constant temperature, no need to set, keep the temperature of fish habitat in the best state at all times. You will find it very easy and happy to take care of pet fish!
  • Precise And Constant Temperature: No need to set, DaToo Fish Tank Heater will automatically keep the water temperature of the fish habitat at 78F. This temperature is very suitable for betta and most tropical fish. When the water temperature is lower than 78F, the heater starts to heat and the red light is on. When the temperature reaches 78F, the heater stops heating and the green light is on. DaToo will always maintain this comfortable temperature for your beloved fish!
  • The Smallest 25W Betta Heater: For most fish lovers who have small fish tanks of 1 to 5 gallons, a small heater means more space for fish. This is the smallest 25W aquarium heater on the market, only 0.2 inches. No matter how small your fish tank is, it can be used perfectly in it, and you can't even find it. Very MINI!!
  • Safe And Durable: Unlike traditional plastic seals, DaToo uses a rubber sealing layer, which ensures that DaToo has better sealing and safety performance, and will never leak electricity or water. Quartz glass material, explosion-proof and crack-proof, more sturdy and durable, without worrying about damage.
  • One Year Warranty & Satisfaction Guarantee: This heater is ideal for 1 to 6 gallon small glass or acrylic desktop aquariums. When in use, it needs to be submerged 100% in water. We provide one year warranty and 24 hours professional customer service. Buy With Confidence!

Description

The Smallest 25Watt Aquarium Heater For Your needs Specification: Power: 25Watt Voltage: 110V~120V/50~60Hz Heater Size: 4.90.90.9inch Power cord: 3.9ft Application: 1 to 5 gallon aquarium Features: - The Smallest 50W Heater On The Market - 78℉ Constant Temperature - Rubber Sealing Layer - Quartz Glass Material - One Year Warranty And 24 Hours Professional Customer Service Why Choose DaToo MINI 25W Aquarium Heater? 1. No Need To Set: DaToo MINI 25W Aquarium Heater will automatically keep the water temperature constant at 78℉. Simple and convenient, very suitable for beginners. 2. The smallest 25W aquarium heater: Only 0.2 inches in length, the smallest 25W heater on the market. No matter how small your fish tank is, it can easily meet your needs. 3. Safe: Unlike traditional plastic seals, DaToo uses a rubber sealing layer for better sealing and safety performance, and will never leak electricity or water. 4. Durable: Quartz glass material, explosion-proof and crack-proof, more sturdy and durable, without worrying about damage. 5. One Year Warranty And 24 Hours Professional Customer Service, Buy With Confidence! Select DaToo Products= Own A Private Aquarium Housekeeper. JUST DO IT, Let’t Go!!

Brand: DaToo


Special Feature: High Accuracy


Color: Black


Age Range (Description): Adult


Included Components: Free Thermometer Sticker


Outer Material: Plastic


Display Type: Digital


Product Care Instructions: Wipe Clean


Unit Count: 1.0 Count


Power Source: Corded Electric


Package Dimensions ‏ : ‎ 5.43 x 2.76 x 2.32 inches; 4.23 ounces


Item model number ‏ : ‎ DT-25A


Date First Available ‏ : ‎ July 17, 2020


Manufacturer ‏ : ‎ DaToo


Best Sellers Rank: #2,881 in Pet Supplies (See Top 100 in Pet Supplies) #3 in Aquarium Heaters


#3 in Aquarium Heaters:


Customer Reviews: 4.4 4.4 out of 5 stars (5,760)


Additional Features: High Accuracy


Display Type: Digital


Power Source: Corded Electric


Upper Temperature Range: 78 Degrees Fahrenheit


Reusability: Reusable


Immersion Depth: 0.9 Inches


LowerTemperature Range: 78 Degrees Fahrenheit


Indoor Outdoor Usage: Indoor


Smart Home Compatibility: Not Smart Home Compatible


Outer Material: Plastic


Product Care Instructions: Wipe Clean


Color: Black


Style Name: Basic


Brand Name: DaToo


Age Range Description: Adult


Included Components: Free Thermometer Sticker


Model Name: DT-25A


Model: DT-25A


UPC: 745408757995


Manufacturer: DaToo


Part Number: DT-25A


EU Spare Part Availability Duration: 1 Years


Unit Count: 1.0 Count


Item Length: 4.9 Inches


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Tuesday, Jun 9

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.

  • Klarna Financing
  • Affirm Pay in 4
  • Affirm Financing
  • Afterpay Financing
  • PayTomorrow Financing
  • Financing through Apple Pay
Leasing options through Acima may also be available during checkout.

Learn more about financing & leasing here.

Similar Products

Top Amazon Reviews

    • Good value for the price.
Size: 25W
Good item that functions as described. The suction however is very poor. The suction cups will not last. It is small and fits neatly where needed. The glass is strong l. Looks nice in small spaces. Easy to install.
Reviewed in the United States on April 26, 2026 by Arvin
    • Cheap for amazing quality !!
Size: 25W
Ive gotten this before and it works so good ! The price is so good for how high of a quality. It fits perfectly in my betta fish tank. And it does very well with staying at the temperature that is needed !
Reviewed in the United States on April 22, 2026 by TJ Dehart
    • Heats small tank, stays in place, temperature not adjustable Heats small tank, stays in place, temperature not adjustable
Size: 25W
Review Image by whitefreeze
Have had it plugged in and running for a few days in my 1.5-gallon tank, and it is working great! The red light turns on when heating; green light when it's at temperature (~78° F), which I've been monitoring via a digital thermometer (temperature seems to stay right between 77.5° and 78.5°). I'm not able to adjust the temperature, but 78° is right around the temperature I'll be needing, anyhow. This heater keeps the temperature in the target range, whereas the 10W heater that came with the tank couldn't, as the water was always way too cold previously. The included thermal tape thermometer kind of works, but is not very accurate and it's really hard to discern the colors; it's nice to have, but I'd recommend something else if you need more temperature accuracy than ±5° and you have a larger tank or a colder room. Also, the suction cup fits the heater well and is nice and soft, holding to the plastic tank really well! (I was a little impressed with that, actually.) ... show more
Reviewed in the United States on February 1, 2026 Reviewed in the United States on February 1, 2026 by whitefreeze
    • They work
Size: 25W
I have ordered a ton of these. So far, most of them seem to work pretty well. They keep the tanks around 78F, give or take a tiny bit. You can’t adjust the temperature since it’s preset. I’d like it if they came in a smaller size and also if they had a shatter proof option. These are glass without an outer casing so they might shatter if they overheat. These are not mini but they’re not huge. They’ll work for a 5 gallon tank or bigger. Don’t use these in anything under 5 gallons. They’re too big for that and might overheat. The heaters are easy to use. Just attach the suction cup, place in tank under water, and plug them in. ... show more
Reviewed in the United States on February 13, 2026 by bee
    • Cute, small, easy to tell that it's working perfectly
Size: 25W
I'm using this for a 3-gallon shrimp tank. It's tiny. It's cute. There is a very belt-and-suspenders approach to being sure this thing is working properly. It lights a little even when it's not heating the water (I expect it's not heating the water when the room is nearly 90 degrees in August). The light is really only visible when the tank is dark and there isn't too much light in the room, but it's a small square by the bottom, just to clearly indicate it is working. I like that assurance. The little thermometer, which is also tiny and out of the way, would be another indicator, again if it weren't August and showing the water temperature in the 80s without the heater. So you can be certain, if there is a problem, you will know. But the ambient room temperature does lead to another point. It's small and I don't think it's that powerful. For me, the room is never going below 70 degrees. I'm in an apartment building with a lot of elderly residents, and the super needs to keep the place warm bordering on hot for them. I need the heater. The water will get too cold for the shrimp without it. But not more than say 10 degrees below their comfort level. If you're thinking a tank in say a garage (I know some people who use that as an office and keep a betta there) and you're prone to reasonably cold winters, then this might not be the thermometer for you. The shrimp seem to think it's a nice platform to sit on. I usually find at least one perched on top. I like especially how deep I can store it and the suction cups keep it firmly in place. If I'm only doing a one gallon water change (they're shrimp -- they have a really low bioload so changing a gallon a week is fine) then I can keep it plugged in while doing the water change and it stays fully submerged the entire time. ... show more
Reviewed in the United States on August 6, 2024 by Ivy Reisner
    • Works well for our 5 gallon tank
Size: 25W
I needed a small heater for a 5 gallon tank that is used to raise our Guppy babies. I was kind of skeptical that this isn't adjustable, but it seems to work well. Any time I've tested, the water temperature is 78 degrees, just like they said it would be.
Reviewed in the United States on April 21, 2026 by Debbie Southers
    • Perfect for Small Tanks
Size: 25W
Needed a small heater for a 5-gallon betta tank and this little plug and play heater did not disappoint. We love it for several reasons. It's fully submergeable so you can place it anywhere. It's simple and pre-programmed to 78 degrees so you don't have to worry about adjusting it or accidentally overheating your fish. It's small so you can tuck it away and easily hide it behind plants and other decor. I've had it for weeks and the temperature is consistently 78 degrees even in an airconditioned environment with ceiling fans running. I have so much faith in this heater that I already bought a second one for the 10-gallon pea puffer tank I'm setting up. If you need the ability to differentiate temperatures for your specific fish, this might not be right for you because it's preset at 78, but it's perfect for our purposes. ... show more
Reviewed in the United States on April 21, 2026 by Irina Kushner
    • Water Temp Measured up to 80 degrees Water Temp Measured up to 80 degrees
Size: 25W
Review Image by Corinne
Review Image by Corinne
I ended up returning this heater. I will either buy a different brand, or just move my betta tank away from the cold window. 1st issue: It recommends a filter with it. Wish I knew that before buying. Heater seems overall like a decent quality for the very cheap price ($7) but just FYI the product states it should be used in a fish tank with a filter, in order to move the water around. Otherwise the heat will stay concentrated in one section and not be effective. 2: Not reliable. I left the heater in a large glass bowl of water overnight and throughout the next day, but it did NOT keep a consistent temperature. The temperature measured between sometimes 78 to 79.5 or even hit up to 80 degrees rather than staying consistent. I noticed it had a hard time staying at temperature and the light would continually change every 30 min indicating that it was heating up again. 3: The section cup it comes with kept coming loose and the heater would float to the top. Helped me best to clamp it down using a chip clip. ... show more
Reviewed in the United States on October 27, 2025 Reviewed in the United States on October 27, 2025 by Corinne

Can't find a product?

Find it on Amazon first, then paste the link below.
Checking for best price...