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FREESEA Aquarium Fish Tank Heater: 50W Small Submersible Turtle Heater with Adjustable Temperature External Controller for Betta | Saltwater | Freshwater | 1-10 Gallon

4.1 out of 5 stars 8,716 ratings
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Size: 50Watt
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Purchase options and add-ons

Material Glass
Voltage 110 Volts
Item Length 3.5 Inches
Brand FREESEA
Color Submersible Heater with External Controller

About this item

  • FREESEA Aquarium Heater: 50w betta fish heater, voltage: 110~120V, is suitable for use in 1-10 gal betta fish turtle tanks and aquariums. The power cord is 5ft, long enough for indoor use
  • Double Safety Protection: When the top part of the turtle tank heater is out of water it will auto shut off. When the actual water temperature is higher than 94°F, it will auto activate the overheating protection and stop heating
  • External Controller: The betta fish heater is adjusted by an external controller, which you can mount on the outside edge of the tank. It’s convenient to adjust temperature that range from 63℉ to 94℉
  • LED Temperature Display: Digital led temperature display shows the real-time temperature and error code on the screen. When the mini aquarium heater is heating, there indicator light above the digit is on red
  • 12-month Warranty: We are committed to providing high quality products and better service with a 12-month warranty. If you have any questions about the turtle heater you receive, please feel free to contact us
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This item: FREESEA Aquarium Fish Tank Heater: 50W Small Submersible Turtle Heater with Adjustable Temperature External Controller for Betta | Saltwater | Freshwater | 1-10 Gallon
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From the brand

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  2. FREESEA is always dedicated to innovate and optimize our products and has a professional after-sales team. We are committed to bring high-quality and stable aquarium supplies and the best after-sales service for each aquarium enthusiast. FREESEA is the most professional aquarium shop you can trust.

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  4. 1.2Gallon Betta Aquarium Starter Kits Square Fish Tank with LED Light and Filter Pump
    FREESEA Aquarium Fish Tank Filter: 20W 400GPH Internal Power Filter 3-Stage Filtration for 75-150...
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    • World-renowned brand, industry benchmark
    • Professional indoor and outdoor aquarium manufacturer

  6. How did we get our start?

    The FREESEA team was started in 2005. We have been in the field of aquarium for more than ten years with the most professional team and first-class after-sales service.

    What makes our products unique?

    We have our own R&D team and factory. Each product is independently developed and designed by our team, and has applied for a patent, which is unique in the market.

    What problem are we solving?

    FREESEA products are rigorously tested and used for a long time before being available in bulk. We focus on providing quality products and services.

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Product Description

Aquarium Heater
Fish Tank Heater
fish tank heater 5 gallon tank
20 gallon aquarium heater
fish tank heater 10 gallon
small aquarium heater

Product details

  • Is Discontinued By Manufacturer ‏ : ‎ No
  • Product Dimensions ‏ : ‎ 2.5 x 1.5 x 3.5 inches; 8.15 ounces
  • Item model number ‏ : ‎ FS28-50W
  • Date First Available ‏ : ‎ September 17, 2017
  • Manufacturer ‏ : ‎ Guang Zhou City Freesea Industrial Co.,Ltd
  • ASIN ‏ : ‎ B075PSPCNY
  • Customer Reviews:
    4.1 out of 5 stars 8,716 ratings

Product information

Material Glass
Voltage 110 Volts
Item Length 3.5 Inches
Brand FREESEA
Color Submersible Heater with External Controller
Wattage 50 watts
UPC 722970219243
Manufacturer Guang Zhou City Freesea Industrial Co.,Ltd
Item Weight 8.1 ounces
ASIN B075PSPCNY
Item model number FS28-50W
Customer Reviews
4.1 out of 5 stars 8,716 ratings

4.1 out of 5 stars
Date First Available September 17, 2017
Item Package Dimensions L x W x H 5.55 x 3.7 x 2.8 inches
Item Dimensions LxWxH 2.5 x 1.5 x 3.5 inches
Brand Name FREESEA
Target Audience Keyword fish, fish tortoise
Size 50Watt

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FREESEA Aquarium Fish Tank Heater: 50W Small Submersible Turtle Heater with Adjustable Temperature External Controller for Betta | Saltwater | Freshwater | 1-10 Gallon

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Important information

Safety Information

This 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.

Customer reviews

4.1 out of 5 stars
8,716 global ratings

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Customers say

Customers find the aquarium heater works well for small tanks and appreciate its simple instructions and easy-to-read display. The temperature accuracy and functionality receive mixed reviews - while some say it maintains the right temperature, others report it being off by 2-3 degrees, and some units fail after 6 months. The size receives mixed feedback, with some finding it perfect for smaller tanks while others note it's too large for their needs. The suction cups have significant issues, with customers reporting they don't work well and come off easily. Value for money is also mixed, with some considering it great for the price while others find it not worth the cost.

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195 customers mention "Heater quality"195 positive0 negative

Customers find the heater to be of good quality, particularly suitable for 10-gallon tanks and small aquariums.

"Nice little heater. I like the digital readout and ease to use. It can hear a 38 gallon tank to 79F if the ambient temp in the room is 70...." Read more

"...The quality of the materials used feels solid, and I expect it to last a long time...." Read more

"...and used it for about a month now and I'm happy to report that every guppy survived...." Read more

"Easy to use nice small unit" Read more

171 customers mention "Ease of use"142 positive29 negative

Customers find the heater easy to use, with simple instructions and a display that's easily readable at a glance.

"Nice little heater. I like the digital readout and ease to use. It can hear a 38 gallon tank to 79F if the ambient temp in the room is 70...." Read more

"...I wish there was option for C temps, but its only for F. Instructions are very simple, immerse heater all the way into water, plug in and press temp..." Read more

"...The installation process was straightforward, and I appreciated the included suction cups that keep the heater securely in place...." Read more

"...Super easy to use. Little light shows up when it’s heating. Easy setup up. Doesn’t get to hot either. My beta loves to prop himself up on it!" Read more

894 customers mention "Temperature accuracy"449 positive445 negative

Customers have mixed experiences with the heater's temperature accuracy, with some finding it perfect for maintaining the right temperature and easy to control, while others report that the heater temperature is consistently 2-3 degrees off.

"Great product, it keeps the aquarium nice and cozy. The only issue is the suction cups aren’t great." Read more

"...It struggled when the ambient room temp was 65 so I used two of them then." Read more

"...My poor Beta was cold without heater =(''' Now that water temp is comfortable for him, which is 22-26C or 72-80F, I can see his spunky self..." Read more

"...It was set at 72 degrees! The button to change temp was not exposed...." Read more

712 customers mention "Functionality"442 positive270 negative

Customers report mixed experiences with the aquarium heater's functionality, with some saying it works great and has no issues, while others mention it stops working after about 6 months of use.

"Great product, it keeps the aquarium nice and cozy. The only issue is the suction cups aren’t great." Read more

"we used this heather before , ; and it works pretty well; we have it in outside water tank for turtles mostly in winter time...." Read more

"...It malfunctioned and KILLED ALL MY FISH overnight!! It was set at 72 degrees! The button to change temp was not exposed...." Read more

"...Pros: -cheap -works well for the couple-several months you have it (also a con?) -decent length of cord..." Read more

169 customers mention "Size"103 positive66 negative

Customers have mixed opinions about the heater's size, with some finding it perfect for small tanks like 5.5 gallon Betta fish tanks, while others note that it takes up a fair amount of space and is bigger than expected.

"...This 50W submersible heater is specifically designed for small tanks, and it’s perfect for maintaining the right temperature for my betta fish and..." Read more

"...This heater is now taking up valuable storage space to be used only in emergency until a new heater can be purchased...." Read more

"...It's been in use for about a year and a half and it fit great in the back sump area with ample room for the pump...." Read more

"...It is compact in length/ height but not in thickness. It takes up more space in 1 gallon tank than one would prefer it to." Read more

138 customers mention "Kills fish"53 positive85 negative

Customers have mixed experiences with the aquarium heater: some report their fish are happy, while others experienced significant losses with multiple fish dying.

"...It malfunctioned and KILLED ALL MY FISH overnight!! It was set at 72 degrees! The button to change temp was not exposed...." Read more

"...I love most is its versatility; this heater is suitable for both freshwater and saltwater tanks, making it a great option if I decide to diversify..." Read more

"...Shortly after, however, I awoke to chaos! All of my tetras were dead, a number of shrimp were as well, and my betta was PANICKING...." Read more

"...is that one of them went full-on nuclear at one point and almost killed my turtle...." Read more

118 customers mention "Value for money"79 positive39 negative

Customers have mixed opinions about the heater's value for money, with some finding it a great product for the price while others consider it not worth the money.

"...Very well worth the money thus far...." Read more

"...I'll try to remember to update if it does go. Pros: -cheap..." Read more

"...I notified Amazon about this. This should have never happened. Lost a lot of money, time and my fish friends." Read more

"...will change as I stand and watch it. Price is right, but the function is all wrong." Read more

121 customers mention "Suction"35 positive86 negative

Customers report issues with the heater's suction, noting that it isn't very strong, the cups come off, and don't work well.

"...The only issue is the suction cups aren’t great." Read more

"...At first the top suction kept coming off, then I adjusted the thick wire and added two suction cups that typically used to holds air lines above it..." Read more

"...process was straightforward, and I appreciated the included suction cups that keep the heater securely in place...." Read more

"...However, the suction cups are really terrible -- even on squeaky clean glass...." Read more

Nice Size But You MUST Use A Controller BE WARNED
3 out of 5 stars
Nice Size But You MUST Use A Controller BE WARNED
This has been a great little heater for my Fluval Evo 13.5g saltwater tank....until today. It's been in use for about a year and a half and it fit great in the back sump area with ample room for the pump. I had it set to 79 degrees and it held the tank at 77 plus or minus half a degree. Unfortunately, after our power went out it reset and defaulted to an extreme temperature and ended up cooking my entire tank like a sous vide. When I caught the problem the thermometer said the tank was at 103.2F! The tank was a year and a half along with about $1k of fish and coral livestock and everything aside from a few large snails got nuked by this heater. To make matter worse, I had the heater on a smart plug for water changes and thought I had turned it off, but clearly I didn't and it ended up melting down through the plastic and caught on fire. That's 100% my fault for not checking to make sure the power was off, but be warned that it can do that without the glass breaking. To that end, even after submerging the heater to put out the fire the glass didn't break which is a testament to the quality of the heating element. Overall, I would be definitely recommend this heater for value, but I'll never trust a heater again without it being plugged into a separate Inkbird controller. Lesson learned the hard, expensive way.
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Top reviews from the United States

  • Amber
    5.0 out of 5 stars Would def buy again
    Reviewed in the United States on April 18, 2025
    Size: 100WattVerified Purchase
    Great product, it keeps the aquarium nice and cozy. The only issue is the suction cups aren’t great.
    Helpful
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  • clubnp
    5.0 out of 5 stars Nice Little Heater
    Reviewed in the United States on February 24, 2025
    Size: 50WattVerified Purchase
    Nice little heater. I like the digital readout and ease to use. It can hear a 38 gallon tank to 79F if the ambient temp in the room is 70. It struggled when the ambient room temp was 65 so I used two of them then.
    Helpful
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  • Ms.Smarte Blonde
    4.0 out of 5 stars Update: Be aware! Heat increase alows bacteria and fungi grow!!!
    Reviewed in the United States on February 17, 2019
    Size: 50WattVerified Purchase
    Update:
    March 1st, after two weeks of using heat, my Bandit start developing darkish spot on few scales near tail fin. First I didnt worry, but then literally in a week, spot got bigger, it started bulging and developed white color stuff on top of black looking scales. I realized heat allowed either fungi or bacteria grow rapidly. His tank is about 3gal, he is alone, no other fish. Got Beta antifungal drops and aquarium salt. Took out all gravel. I use distilled water with Betta complete water conditioner. Now I am using API salt and Pimafix fungal infection drops. For about last 3 days Bandit is lethargic and most of the time stays low or hides in his house. He was happy for first two weeks with heater hanging around it all the time. I never had any fish or Betas before, I got him in August 2017, he was healthy and spunky til recently. Now he doesnt seem to be hungry, I watch him for about 15 min to swim up to eat. Right now he sleeps in his house and wont come out. I am heart broken to think that I might have make him sick by heating up water. I change water every couple weeks. Bandit has fresh 3 live Marimo balls, which suppose to absorb impurities. I have water pump for circulation, heater right now is on 72, just about low comfort level. I been using Antifungal drops since Mar 5th, dont see any improvement yet, but it doesnt seem getting worse either. I absolutely hate to think I might have caused him getting sick! I spent so much money on this little guy for his comfort, but I didnt think I could cause him harm =('''
    Apparently I need to learn how to care properly for Bettas, since I never before had any fish. I got him in Petco in August 2017. When I walked by Bettas, they are in those tiney round containers laying there docile, he was the only one who went bezerk and started pounding on container, which made me look at him. He was looking at me and I heard this voice in my head " get me out of here!" I even looked around thinking where did this voice came from?
    Next thing I know I reach for his container...That day I dropped over 100bucks. 3gal tank, gravel, food, water drops etc. I came home thinking how did that happen and how do I best care for him? I went to Petco to buy litter for my Izabella and ended up with Bandit. I love him, he was happy in his new home, being able swim around. Now he is just lethargic, hiding in the house. I am sure heat has something to do with it. Now I am trying to reverse damage. For people like me, who dont know much about Betas, this is lesson to be learned.
    Original review:
    I got this heater Feb 14th, plugged in and it heated up quite fast, I would say in 30min temp was warming to his comfort level. I set it for 78F. I have one Beta boy, on these cold arctic days water temp got below his comfort zone, as per thermometer. My Bandit was laying low and wouldn't swim around much. When I plugged in heater, he was drawn to it immediately, he was staring at it for a while and then just hanging around it for warmth. My poor Beta was cold without heater =(''' Now that water temp is comfortable for him, which is 22-26C or 72-80F, I can see his spunky self swimming around happy! His water thank holds almost 4gal, I have gravel, water pump, not filter, and heater, and I can see my Bandit is happy. Now he has better appetite also, and I don't have to watch him for 15min before he swims up to eat, now he eats right away. I realized that he wasn't comfortable in colder temps and I am very glad I got this heater for him! Very well worth the money thus far. I wish there was option for C temps, but its only for F. Instructions are very simple, immerse heater all the way into water, plug in and press temp button. I am glad for this purchase and my Bandit is happy! I recommend this heater. 4 stars only because no C option, otherwise 5 stars.
    31 people found this helpful
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  • ElizaMe
    5.0 out of 5 stars good help
    Reviewed in the United States on December 29, 2024
    Size: 75Watt_Verified Purchase
    we used this heather before , ; and it works pretty well; we have it in outside water tank for turtles mostly in winter time. and sometimes we found them on top of it . this means that it keeps them warm enough . When is too cold we put them inside the house and in the summer no need .
    we just have to chenge them after rwo or three years depending of the used. we keep it on, all day during the cold.
    the tank is 25 gallons.
    Helpful
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  • Surf and you shall find
    1.0 out of 5 stars IT KILLED ALL MY FISH!
    Reviewed in the United States on April 3, 2025
    Size: 75Watt_Verified Purchase
    I bought this on October 27, 2024.
    It was working fine until last night. It malfunctioned and KILLED ALL MY FISH overnight!!
    It was set at 72 degrees! The button to change temp was not exposed. This morning it was glowing orange and with my temp gun it was 122 degrees!!!!!! 6 months old and apparently the safety shut off doesn’t work WTF!
    I have had different heaters in the past and this NEVER HAPPENED!
    $150 of fish GONE!

    NEVER BUY FROM THIS PROBABLY China made company!
    Customer image
    Surf and you shall find
    1.0 out of 5 stars
    IT KILLED ALL MY FISH!

    Reviewed in the United States on April 3, 2025
    I bought this on October 27, 2024.
    It was working fine until last night. It malfunctioned and KILLED ALL MY FISH overnight!!
    It was set at 72 degrees! The button to change temp was not exposed. This morning it was glowing orange and with my temp gun it was 122 degrees!!!!!! 6 months old and apparently the safety shut off doesn’t work WTF!
    I have had different heaters in the past and this NEVER HAPPENED!
    $150 of fish GONE!

    NEVER BUY FROM THIS PROBABLY China made company!
    Images in this review
    Customer image
    2 people found this helpful
    Helpful
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  • C
    5.0 out of 5 stars Great
    Reviewed in the United States on November 5, 2024
    Size: 50WattVerified Purchase
    I recently purchased the FREESEA Aquarium Fish Tank Heater, and it has been a fantastic addition to my aquarium setup! This 50W submersible heater is specifically designed for small tanks, and it’s perfect for maintaining the right temperature for my betta fish and other aquatic friends.

    One of the standout features of this heater is its adjustable temperature external controller. Setting the desired temperature is a breeze, and the clear display allows me to monitor it at a glance. I’ve noticed that my fish are much more active and healthy since I started using this heater, which I attribute to the consistent temperature it maintains.

    The design of the heater is compact and sleek, making it easy to fit into my 1-10 gallon tank without taking up too much space. It’s also submersible, which means I can place it exactly where it’s needed for optimal heating. The installation process was straightforward, and I appreciated the included suction cups that keep the heater securely in place.

    I was also impressed by how quickly the heater warms up the water. It doesn’t take long to reach the desired temperature, and I feel confident that my fish are comfortable and safe. The heater has built-in safety features, such as over-temperature protection, which provides additional peace of mind.

    What I love most is its versatility; this heater is suitable for both freshwater and saltwater tanks, making it a great option if I decide to diversify my aquarium in the future. The quality of the materials used feels solid, and I expect it to last a long time.

    Overall, the FREESEA Aquarium Fish Tank Heater is an excellent choice for anyone with a small aquarium. It offers reliable heating, easy temperature control, and peace of mind for fish owners. I highly recommend this heater for keeping your aquatic pets happy and healthy!
    One person found this helpful
    Helpful
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Top reviews from other countries

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  • Bestwater
    5.0 out of 5 stars Gute qualitet
    Reviewed in Germany on August 4, 2023
    Size: 100WattVerified Purchase
    Gute qualitet
    Report