PULACO 25W Small Aquarium Submersible Betta Heater with Free Thermometer Strip, Under 6 Gallon Fish Tanks (Preset Temperature 78℉)
Original price was: $11.99.$9.99Current price is: $9.99.





Price: $11.99 - $9.99
(as of Oct 10, 2025 17:03:07 UTC – Details)
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PULACO provides you with quality Aquarium equipment and services. We are committed to being the best Aquariums store you can trust.
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Our online store started on 2018, focus on aquarium products supply. dedicated to build a professional & reliable aquarium equipment brand.
Why do we love what we do?
Our co-work parterners are aquarium fans, we love our aquarium career and strive to supply safe, reliable aquatic products to all aquarium fans.
What problem are we solving?
All products we select, are strictly tested and long term used before bulk supplying. We are focused on providing reliable aquarium equipment to all aquarium fans and help them to create a pleasant and worry saving aquarium environment.
Product Dimensions : 5.5 x 1.2 x 2.7 inches; 4.2 ounces
Item model number : 25W
Date First Available : November 18, 2019
Manufacturer : PULACO
ASIN : B081VN41FQ
Best Sellers Rank: #3,243 in Pet Supplies (See Top 100 in Pet Supplies) #5 in Aquarium Heaters
Customer Reviews: 4.3 4.3 out of 5 stars 11,408 ratings var dpAcrHasRegisteredArcLinkClickAction; P.when(‘A’, ‘ready’).execute(function(A) { if (dpAcrHasRegisteredArcLinkClickAction !== true) { dpAcrHasRegisteredArcLinkClickAction = true; A.declarative( ‘acrLink-click-metrics’, ‘click’, { “allowLinkDefault”: true }, function (event) { if (window.ue) { ue.count(“acrLinkClickCount”, (ue.count(“acrLinkClickCount”) || 0) + 1); } } ); } }); P.when(‘A’, ‘cf’).execute(function(A) { A.declarative(‘acrStarsLink-click-metrics’, ‘click’, { “allowLinkDefault” : true }, function(event){ if(window.ue) { ue.count(“acrStarsLinkWithPopoverClickCount”, (ue.count(“acrStarsLinkWithPopoverClickCount”) || 0) + 1); } }); });
【Betta Heater】: This Fish Tank Heater should be 100% submerged into water, Ideal for small glass or acrylic desktop aquariums up 1 to 6 Gallons, not suitable for less than 1 gallon tank.
【Quick and Easy Installation】: Vertical or horizontal placement using, Aquarium heater automatic temperature control 78℉, no need to adjust temperature, easy to operate, fishes happy.
【How it Works】: Plug in, red light turns on, the heater will start working until water temperature up to 78°F, and red light off, then the green light will turn on, heater stop working and keeping constant temperature 78°F. Accuracy:±3°F
【Note】: Do not operate or leave product plugged in when your water tank is out of water, heater should be fully submerged into water. Please install a water pump or filter to help water circulating while heating.
【SATISFACTION GUARANTEED】: Our Aquarium Heater is built with durability in mind and safety for every design. In the remote possibility that you’re 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.
Customers say
Customers find the aquarium heater perfect for small tanks, particularly 4 and 8 gallon ones, and consider it well worth the price. However, the temperature control receives mixed feedback – while it maintains a consistent 78 degrees, some report their tanks staying below 70 degrees. Moreover, the heater’s functionality and heat level are mixed, with some saying it works well while others report it stops working completely and gets too hot. Additionally, durability is a concern as customers report the glass casing exploding in the tank, and there are safety concerns as it has killed multiple fish.
13 reviews for PULACO 25W Small Aquarium Submersible Betta Heater with Free Thermometer Strip, Under 6 Gallon Fish Tanks (Preset Temperature 78℉)
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Original price was: $11.99.$9.99Current price is: $9.99.
William Floyd –
Worth it!
I bought this heater for my 5 gallon betta tank and it does a good job. Itâs a simple setup – just place in the tank and plug-in. The temp strip that comes with it shows the water at a constant 76-77 so thatâs pretty close to the 78. Not sure if the temp strip is inaccurate or if the heater is constant at that temp? Either way my betta has visibly perked up with it, so I am happy and so is he!The heater will turn red when itâs heating and green when maintaining heat. I was a little worried at first when it was changing between the colors so frequently but that was after I initially installed it – I believe it was trying to slowly heat the water without shocking the fish with a vast change. Now it only changes a few times and seems to maintain temp well.Overall this is definitely worth the money and fits great in my tank – would absolutely recommend.
MiniAmi –
Very efficient
This heater works great! I have it in a 3 gallon tank for quarantine and I also have it in a 16 gallon tank and still works! I monitor the water temperature everyday just for good measure. I have also found that in the summer, I don’t use it as much because the tank stays warm naturally and I don’t want to overheat my tank. Where I live gets really hot up to the 3 digits.In the spring, I find these very useful as it really regulates the water and keeps it between 76F and 78F and I think my tank is oversized for this heater because it states that it’s for under 6 gallon only but it still works in my 16 gal tank. It’s easy to know when it’s working because it turns from red to green when it reaches the right temperature.It’s small and doesn’t take too much space. My Pleco and other fish likes to stay around it and it doesn’t hurt them even when they get close to it. I will probably upgrade to a bigger one when winter comes for my large tank. I don’t want to overwork the heater but for now that it doesn’t get cold in my area it works perfectly. It’s so efficient that I ended up buying two of them. I highly recommend it!
Kylie –
Works Great for My Small Tank
Compact, reliable, and keeps my betta tank the perfect temperature. Easy to adjust and install.
Vicki Apple –
Great Heater, Thermometer doesn’t work at all
The heater does exactly what it should. It keeps my 5.5 gallon tank right at 78 degrees F. I installed it horizontal about an inch off the substrate in the back of the tank and my betta loves hanging around it. It’s a little worrisome, but I figure he knows what’s best for him. ?? The thermometer that sticks to the outside of the tank doesn’t work at all. I left it for a week and it never displayed a temp. I bought a suction thermometer that goes on the inside of the tank. I put it on one of the sides and it verifies my temp is always 78. Overall, very happy with the purchase.
Nicole D. –
This heater fried my neighbor’s fish! The water was steaming when he woke up in the morning!
I bought this heater for my betta tank and it worked just fine, although I switched to a Hygger heater because of the following…I suggested this heater to a neighbor of mine that got a new betta. Everything was fine the first day, but when he woke up in the morning, his fish literally fried to death. The water was so hot that it was steaming! The temperature gauge was flashing and the heater completely malfunctioned. I was horrified and felt guilty that I had recommended it to him. I did some research, read reviews, and found that the Hygger heater was way more accurate and SAFE! I highly recommend that you DO NOT BUY this cheap heater. Don’t take the risk.
Bobby Magic –
SATISFACTION GUARANTEED!
First of all, I buy a LOT of STUFF on Amazon and I almost never give reviews. Why? Because I’d be spending an un-Godly amount of time just writing reviews so I skip it. However, I HAVE written reviews. What motivates me to write a review when usually I just SKIP IT? What motivates me is when I receive a product from a buyer on Amazon that blows my socks off and is BEYOND my expectations. I have bought many thermometers over my fish keeping years. Left the hobby for awhile (I should say, “Left the Lifestyle’) & when I came back LO & BEHOLD, Nano Tanks are the rage. Nano tanks and I am very fond of planted glass bowls (I’m about to try a new Walstad bowl- CYS-EXCEL 13.5″h x 15.25″ across on Amazon) Consequently, I have purchased many, many small heaters for my smaller glass bowl and a 7.11 gallon 11.8″ x 11.8″ x 11.8″ Landan Nano Cube (Amazon) in which I wanted a small heater that couldn’t be seen. ALL the small heaters I tried were failures at maintaining the status quo temp I was seeking. They couldn’t hold 78°F water temp. no matter how small the aquarium / bowl. So I had this big-ass honkin’ heater in my 11.8″ cube and THAT did a great job but too bad it’s HUGE and is easily seen as a big ass THINGY in my cube. I stopped heating the bowl. The little Nano heaters I was buying for the bowl couldn’t even maintain my bowl temp. and that was my small bowl at about 2.5-3 gals. Now I just bought the larger 4 gallon bowl and it LOOKS Huge but still small relative to the cube. So I’m thinking…I better look HARDER for a good mini-heater and I landed on this PULACO 25W heater. One of my criteria for buying on Amazon are the reviews. Not just written review content but HOW MANY reviews the item has. The PULACO 25W heater has over 10,500+ reviews! WHAT!? Now, I’m interested! It’s PRE-SET to 78°F so that’s what I want in my Nano and my bowl. If you have a situation where you are keeping animals or plants where you want it warmer or cooler i.e. you don’t want 78°F. Then this is NOT the heater for you. Seventy-Eight Degrees. That’s it. But it’s a reliable 78°F and I check it regularly two different ways. You will actually receive a small ‘Stick On The Side’ thermometer which I stuck on the Nano side wall. I also bought an Etekcity Infrared Temp Gun (Amazon) which I take temps of everything. I heat replacement water for my Nano tank up to the current temp and I’m taking their temps with the Infrared gun. Both the cheap ‘stick on’ sticker and the Infrared gun confirm—> 78°F !!!! I was shocked and surprised that this little guy…the PULACO 25W Small Aquarium Betta Heater with Free Thermometer Strip did EXACTLY what it was advertised to do. Heats water up to 78°F and holds it steady at that temp. I even experimented by using it for a week in the 7 gal. Nano and it held 78°F as advertised. So, despite it’s diminutive size which I LOVE LOVE LOVE it’s only supposed to be rated up to 6 gallons. To be honest, my Nano probably has 6 gal. in it once I subtract the substrate, the hardscape, the plants, etc. Anyway this little PULACO 25W is also a PLUG ‘N PLAY. All you do is plug it in! It’s easy to use and you can easily hide it for your viewing pleasure! I just want to comment on the negative reviews. I know that there is mixed feedback on durability, performance, quality heating value (whatever the definition of THAT is!) but I have not had an issue and I’ve been using the hell out of it for two months. I don’t understand the complaints about glass breaking? Now, I haven’t been rough with this PULACO 25W glass heater, I haven’t bumped it against the aquarium or bowl. I believe that ALL GLASS HEATERS are prone to breakage (especially if you have some age on that glass heater!) and YES, I believe you could break this little PULACO with the wrong move (glass is breakable!) but I find it hard to believe that the glass would break with normal use. Just sayin’…how do you break a glass aquarium heater? It doesn’t take much imagination to picture it breaking…now picture HOW it got broken. Another interesting aspect of this heater is that on my little 11.8” cube (about 6 gals) I am running not one, but TWO EHEIM Canister filters. Both are the small EHEIMs (Filter 2211 -‘Classic 150’) but still… I am moving a LOT of water using two EHEIM Canisters on that little cube but that little PULACO 25W handles it, keeping the water at 78°F even though I am moving so much water through the two canisters. I think that it’s not only interesting but important to know that the little heater is a solid choice. LAST BUT NOT LEAST—-> remember my headline? SATISFACTION GUARANTEED! Here is your promise from the manufacturer:â ãSATISFACTION GUARANTEEDãOur Aquarium Heater is built with durability in mind and safety for every design. In the remote possibility that youâre 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.And, of course, if you find that you don’t like it right away, return to Amazon for your refund. And NO, I don’t work for the PULACO people in any way, shape, or form. Out of all the crap I buy on Amazon, I write this because it’s a product that I believe in and I have run the gamut of small heaters, all the rest failures.
Fix-it Man –
25-watt Submersible heater
It functions well and I can use it horizontally too. The fixed temperature design is much better. The temperature is about right according to the instructions. I have not noticed the green light flashing when it is above 78*F though. But having the changing LED lights in better than the old fashion hang-on heaters with just a neon pilot light. Those you have to maintain the water level for it to work right too. For the cost of this heater, it seems to be working well. Time will tell how durable it is.
Chloe –
worth it
light goes red then green shortly after so itâs working. compact for my tank. love it so far. highly recommend
Rita Chávez Pérez –
Muy bueno, ya tiene dos años y sigue sin problema alguno.
Cole VH –
Keeps the aquarium at a perfect temperature for my betta, keeping him comfortable and happy.
Dr Arjun –
Never expected this. It has mentioned prefixed temperature at 78F.I installed on my tank in the nightBy morning the heater has malfunctioned and burnt my Betta fish and money plant.Heater was immersed properly- because of overheating- there was evaporation and water loss
rituporna borah –
Connected it before 6 hours, heated the tank only once at the beginning up to the point and after that temperature is just dropping and dropping. Red light is on from the beginning. I’ve even touched it to feel if it is warm but not at all.
AnnelysM –
El calentador es efeciente y funciona de maravilla en nuestro acuario de 3.6 galones.