Search  for anything...

FREESEA 25/50/100/200/300 Watt Aquarium Heater with Aquarium Submersible Thermometer

  • Based on 8,169 reviews
Condition: New
Checking for product changes
$16.99 Why this price?
Save $9.00 was $25.99

Buy Now, Pay Later


As low as $4 / mo
  • – 4-month term
  • – No impact on credit
  • – 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, PayTomorrow, Affirm, Afterpay, Apple Pay, and PayPal. 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

This item is eligible for return within 30 days of receipt

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 Monday, Nov 25
Order within 5 hours and 52 minutes
Available payment plans shown during checkout

Pattern Name: 50Watt


Features

  • 50 Watt Heater: This Aquarium heater is suitable for 5 to 15 gallons aquariums, Length - 6.8 inch,voltage 110-120V, power cord is 4.0 ft, please choose the right wattage aquarium heater according to our size chart.
  • Temperature range: 63F~95F , It is very easy to adjust the temperature you need, we also deliberately give each customer a free diving thermometer, you can observe the water temperature of the fish tank at any time.
  • Intelligent temperature control:Automatic constant temperature function, when water temperature reaches to specified temperature value, heater will automatically stop heating, when water temperature is lower than the set temperature, heater will automatically start heating. Furthermore, Automatic safety shut-off feature, and overheating protection.
  • Note: 1. Aquarium heater is 100% submersible use only, during its heating time, heater must be 100% submerged into the water.,Please unplug the power supply when cleaning the fish tank or aquarium water changes. 2. Heater rod is suitable for people over 16 years of age. Children or minors should be under adult guidance or supervision.
  • SATISFACTION GUARANTEED: Gain the confidence to go hard with us! Our Aquarium Heater is built with durability in mind and safety for every design, In the remote possibility that youre not satisfied with our product, just contact us, and we will gladly give you a new Aquarium Heater replacement. 12 Month Warranty and 24 Hour Professional After-sales Service.

Product Dimensions ‏ : ‎ 11.3 x 3 x 2 inches; 7.37 Ounces


Date First Available ‏ : ‎ June 10, 2019


Manufacturer ‏ : ‎ FREESEA


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Monday, Nov 25

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.

Top Amazon Reviews


  • Cooked my fish alive!!!
Pattern Name: 25Watt
Killed my betta fish!!! I would NOT recommend this to my absolute worse enemy!!!! Set it to 75ish, give or take a degree (because the dial is so hard to decipher), left for work, came home 6 hours later and my poor fish was COOKED!!!!! The MOST traumatic thing to see when it's not even a blip on your radar that it could happen! My digital thermometer maxed out at 99 degrees and I assure you it was much hotter than that when I stuck my hands in the water! Worst experience ever! Had to lie to my son so he wouldn't be as traumatized as I. Just pllllease buy a mercury thermometer for accurate water temp and a heater from elsewhere. Please!!!! ... show more
Reviewed in the United States on September 17, 2020 by Amazon Customer

  • It Works
Pattern Name: 25Watt
I have this heater in a 1.5 gallon tank for a betta. It took some time to get the right temp setting. I had to go lower on the thermostat in order to get the right temp. Example: I set it on 78F in order to get 82F. The thermostat is nice, but too big for my tank. It'll work good in a larger tank if that is what you have. The heater has a light that shows ON when it is heating, and it goes off when the temp is reached. I recommend this heater, but you need to watch it closely at first so you don't freeze/cook your fish, as I said above, the thermostat itself is a bit off. ... show more
Reviewed in the United States on September 24, 2019 by Kelly

  • Good Heater for Smaller Tanks
Pattern Name: 25Watt
I was apprehensive about getting this heater initially, but the one that was recommended to me way way too big for our tank, so I took a leap of faith and it's been good so far. We do keep it about 3-5 degrees colder than what I want my tank at judging by all the reviews of it "cooking" people's fish. Started out at the temp the tank was at initially (74) and it seemed to be heating consistently so I turned it up to 80, and in turn it heated the tank to 83 which I know is borderline too hot for a Betta Fish. So I turned it down to about 75-77 and it keeps the tank around 78/79. I don't use the thermometer that came with the tank (we have a decorative one my daughter LOVED) and I keep it closer to the heater to make sure it doesn't overheat the tank. I think it depends on how big your tank is (ours is 3 gal) and if it's glass or acrylic. I would HIGHLY recommend getting it before you get your fish if you can... and if you don't start it at the temp your tank already is and SLOWLY turn it up. Wait at least 24-48 hours before turning up the temp if it's not warm enough. The knob is tricky to turn - which it wasn't so stiff - and the readings are a little vague and not super specific but once we got it to the right time it's been consistent. My Betta also likes to hide near it and it doesn't seem to bother him or hurt his fins at all. I would recommend this for tanks 5 gal or smaller. ... show more
Reviewed in the United States on February 6, 2020 by Jen K Jen K

  • danger of electric shock
Pattern Name: 50Watt
water leaked into the heater after a couple of days, energizing the whole fish tank, super dangerous item
Reviewed in the United States on October 3, 2019 by SvenDieter

  • Keeps temp at 78⁰F for my 2.5 gallon tank
Pattern Name: 25Watt
UPDATE: Today I went to feed my fish and saw that the top of the heater was covered in a layer of slime or something? (See pic) Not sure what it is or if this should be happening..... I'm hoping this won't cause the heater to malfunction. ORIGINAL REVIEW: So far so good. Took me a day and constant monitoring to finally get the right temperature (~78⁰F) for my betta and shrimps in my 2.5 gallon tank. The temperature options available skip from 73 to 77. If you put the dial on 77, the tank gets a little too warm (temp went up to 81 and kept going up). So I put it back on 73 but temp dropped to 76. Finally I put it on the line right between 73 and 77, and now the temp stays around 78⁰F. Water heater also comes with a free suction thermometer. I used a digital temperature gauge from ZooMed (which I use for my tortoise) to make sure it was accurate. There was only ~0.1 difference. PRO: • adjustable • turns off automatically when it reaches the set temp • light turns on when heater is on • comes with a free digital thermometer CON • doesn't have a built in thermometer like my old water heater did (comes with a free one but takes up room, especially in a small tank). • doesn't heat up to the set temperature (heats hotter) but luckily it's adjustable Since it heats hotter than set and it goes up to 95, I believe the 25 watt would be sufficient for a 5 gallon. ... show more
Reviewed in the United States on May 26, 2020 by Kim Kim

Can't find a product?

Find it on Amazon first, then paste the link below.