Best Aquarium Heaters of 2025

"I absolutely love this heater! I felt guilty for my fish in the colder environment, but now with this heater, my tropical fish are thriving. It's lightweight, easy to install, and durable. I just press a button to set the temperature, and it stays consistent!"

"I really enjoy the enclosed design of this heater. It's sleek and has been working perfectly for my 50-gallon tank for four months. The 1-button interface makes it easy to use, and for the price, it's unbeatable!"

"This heater is reliable and efficient, keeping a consistent temperature for my fish. The adjustable thermostat is user-friendly, and I've been impressed with how quickly it heats the water. The solid build quality gives me confidence, and my fish are thriving!"

"I installed this water heater for my 5-gallon fish tank and it's consistently holding the temperature at 77°F. I chose this because it's a Tetra product, which I trust for reliability. I appreciate that it operates quietly and I haven't noticed any leaks. Overall, it's functioning exactly as I expected!"

"I really like this heater. The previous one I had caused electrical surges that resulted in losing 20 fish. This one is designed for submersion, unlike the ones that come with aquarium setups. The only downside is that I can't adjust the temperature, but I bought three of these heaters because they work so well!"

"I was thrilled to find that this heater kept my 3-gallon tank warm and my betta happy until it suddenly stopped working. Despite the indicator light showing green, the water was ICE COLD the next morning. I reached out to Tetra customer service for help, but the representative was rude and unhelpful. I was disappointed with their lack of support!"

"I found it very easy to set up and adjust the temperature. The LED readout is perfect; I'd definitely buy it again."

"After replacing our old heater, I came across this one and felt confident in my purchase. It’s user-friendly and maintains our tank at a steady 76 degrees Fahrenheit for a week now."

"I was thrilled with how quickly this heater worked. I set it to 72 degrees, and within 30 minutes, my 55-gallon tank reached that temperature. I’m very happy with this product!"

"I have a Fish Room with 39 tanks, and over time my old hang-on tank heaters died, prompting me to find a reliable heater at a fair price. The Fluval heaters get the job done. They work as they should and have lasted well for me. I do use a laser thermometer to check the temperature since the numbers don't align perfectly with the actual temperature."

"I've been using this heater for about 11 months now, and it still works great. I transferred it from a 20-gallon tank to a 40-gallon tank, and it keeps the temperature steady without any issues. The blue light indicator is convenient for knowing if it’s working."

"I've owned a lot of Fluval products over the years, including filters and heaters. I always recommend their products because they are durable and long-lasting, making maintenance easier for anyone passionate about fishkeeping."

“I needed a heater for my betta tank as it was getting colder, and this was perfect! Installing it was a breeze; I just plugged it in and secured it with a suction cup below the water level. It keeps the tank water slightly above room temperature, which is ideal for my fish. I did pay attention to the reviews about it overheating and potentially harming pets, so I monitored it closely on the first day. Thankfully, I’ve never faced any issues! Definitely worth the price.”

“After setting up a 6-gallon shrimp tank in my chilly home office, I needed a heater since the water was too cold for a betta. This heater seemed like a solid option as it claims to measure temperature, reducing the need for an extra thermometer. I noticed a little variation in temperature throughout the tank, but using a probe thermometer at the farthest point from the heater showed only a 2-degree difference. Gradually raising the temperature each day is working out well for me.”

“I’m really pleased with this heater for my 5-gallon tank! It automatically shuts off when the water reaches 78 degrees, which is exactly what my betta needs. The setup process was incredibly simple, and the suction cup is impressively strong. Although it’s a bit smaller than I expected, I actually like that about it!”

“I got a great price for this heater after my other one failed. It maintains the temperature well, reading exactly 78 degrees after hours of use. The water looks clearer, and hopefully, it will help with the brown algae. The only downside is its size; it can’t touch the gravel and tends to dip a bit.”

“I purchased this heater a couple of months ago. Initially, it worked well, but now the temperature setting is off. I set it to 80 degrees, yet it reaches 86 degrees. I’m disappointed with Marineland's products, as I’ve had issues with other items, including a cracked tank and a leaking filter.”

“I've been using this heater for a couple of years now. The good news is it hasn't caused any damage. The bad news is that the dial numbers have faded, making it hard to read the settings. I now have to rely on a thermometer to check the temperature.”

"I use this for my 75 gallon Rio Negro biome tank. It keeps the temperature rock steady, and it's easy to see and change the set temperature."

"I have a 55 gal freshwater tank with an Eheim canister filter. After adjusting the heater's position, it kept the temperature within half a degree of the set value. The digital temperature display is a neat feature!"

"The digital readout is fantastic. Once correctly positioned, it holds the temperature well. I initially had issues after a water change but resolved it by placing it near an airstone. Now, it works flawlessly!"

"I purchased three heaters to replace my Aqueon heaters that failed to heat past 74 degrees. I'm thrilled with this product! It maintains the desired temperature perfectly across my 22-gallon tanks, and I even have a backup heater. It’s been a lifesaver during these cold days; my tanks are holding temperature without a hitch!"

"I've been using this heater for nearly a year without any issues. I did have to turn it down a bit because my 100-gallon tank gets quite warm, but overall, it's performed well."

"I had a devastating experience with this heater. Just after I added water to my 10-gallon tank, it started smoking and melted all the plastic clips. I lost five fish and several shrimp, which is incredibly upsetting. I had high hopes based on the great reviews, but this has been a nightmare."

"I've been looking for a smaller heater that fits perfectly in my aquarium, and this one does just that. It looks nice and works well!"

"After using this heater for a few days, I'm really pleased. I had some issues with temperature accuracy, but once I adjusted it, everything has been great!"

"I bought this heater based on its good reviews, and I'm glad I did. It maintains the temperature consistently and has been a solid replacement for my broken one."

"I find these heaters to be FANTASTIC! Unlike most heaters, they actually run a degree or two hotter than set, which is great for my smaller tanks. The included thermometers are a nice touch for monitoring my axolotls. 10/10, would buy again!"

"After struggling to find a reliable heater for both my freshwater and saltwater tanks, I decided to try the Orlushy Submersible Aquarium Heater. It offers precise temperature control and the 500W power keeps my 75-gallon tank at the perfect temperature. The durable construction gives me confidence in its longevity. Overall, I highly recommend it!"

"I initially bought a 300W heater for my 55-gallon tank, but it couldn't keep the temperature up. Switching to the Orlushy 500W was a game-changer! Now, my tank heats up into the 80s without issue. This product is a great value, especially considering the cost of fish these days!"