--- product_id: 461489991 title: "AquaMiracle Mini Aquarium Heater 20W Small Fish Tank Heater for 2-4 Gal Tanks, Digital Display Thermostat Betta Heater with Dry-Run & Overheat Protection, Memory Function" brand: "aquamiracle" price: "$36.11" currency: USD in_stock: true reviews_count: 7 url: https://www.desertcart.us/products/461489991-aquamiracle-mini-aquarium-heater-20w-small-fish-tank-heater-2 store_origin: US region: United States of America --- # 2.36” ultra-compact size ±1°F precise digital thermostat Dry-run & overheat safety AquaMiracle Mini Aquarium Heater 20W Small Fish Tank Heater for 2-4 Gal Tanks, Digital Display Thermostat Betta Heater with Dry-Run & Overheat Protection, Memory Function **Brand:** aquamiracle **Price:** $36.11 **Availability:** ✅ In Stock ## Summary > 🌊 Tiny heater, huge impact—keep your tank perfectly cozy! ## Quick Answers - **What is this?** AquaMiracle Mini Aquarium Heater 20W Small Fish Tank Heater for 2-4 Gal Tanks, Digital Display Thermostat Betta Heater with Dry-Run & Overheat Protection, Memory Function by aquamiracle - **How much does it cost?** $36.11 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.us](https://www.desertcart.us/products/461489991-aquamiracle-mini-aquarium-heater-20w-small-fish-tank-heater-2) ## Best For - aquamiracle enthusiasts ## Why This Product - Trusted aquamiracle brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Safety-First Design:** Automatic shutoff prevents overheating and dry-run damage—no more fishy disasters. - • **Smart Memory Recall:** Remembers your last setting after power outages, so your tank stays stable effortlessly. - • **Versatile Aquatic Use:** Ideal for freshwater, marine tanks, turtles, pet fountains, and even plant seedlings. - • **Thumb-Sized Powerhouse:** Fits discreetly in nano tanks without sacrificing heating performance. - • **Precision Temperature Control:** Digital display with dual readings ensures your aquatic friends thrive at the perfect 64-93°F range. ## Overview The AquaMiracle Adjustable 20W Small Aquarium Heater is a compact, thumb-sized submersible heater designed for 2-4 gallon tanks. Featuring a precise digital thermostat with ±1°F accuracy, dual temperature display, and advanced safety protections including dry-run and overheat shutoff, it ensures optimal and safe heating for bettas, turtles, and small aquatic environments. Its memory function retains settings after power loss, making it a reliable, versatile solution for both freshwater and marine setups. ## Description Full description not available ## Features - SUPER MINI SIZE – This small aquarium heater is “thumb size” - only 2.36” (6cm) in length. Great for nano tanks / betta tanks. The innovative super mini size perfectly solves the headache of the fish keepers on the traditional heaters! Takes up less space, easy to hide, but in full power! Temperature range is 64-93F, for 2-4 Gallon tanks. - ACCURATE TEMPERATURE – Thanks to the intelligent inverter technology, with the in-built chips this thermostat keeps the heater at a constant temperature at an accuracy of 1F, much more accurate than the traditional knob-controlled heaters. The thermostat shows 2 readings – the current temperature and the set temperature – very easy to operate. - DRY RUN / OVERHEATING PROTECTION – Full consideration of safety. With the multiple protections this fish tank heater will stop working when the water level is lower than the minimum water level or when the water temperature exceeds 97F. You are free from “cooking fish”! - MEMORY FUNCTION – The last setting is stored in the thermostat. In case of a power cut, when the power recovers the heater will follow the last setting. - MULTIPLE USES – This heater can be used for both fresh and marine water. It can be not only used as an aquarium heater, but can also work for turtles, pet fountains, and plant seedling. ## Images ![AquaMiracle Mini Aquarium Heater 20W Small Fish Tank Heater for 2-4 Gal Tanks, Digital Display Thermostat Betta Heater with Dry-Run & Overheat Protection, Memory Function - Image 1](https://m.media-amazon.com/images/I/61gm+rxBmwL.jpg) ![AquaMiracle Mini Aquarium Heater 20W Small Fish Tank Heater for 2-4 Gal Tanks, Digital Display Thermostat Betta Heater with Dry-Run & Overheat Protection, Memory Function - Image 2](https://m.media-amazon.com/images/I/71Z-YpZDOiL.jpg) ![AquaMiracle Mini Aquarium Heater 20W Small Fish Tank Heater for 2-4 Gal Tanks, Digital Display Thermostat Betta Heater with Dry-Run & Overheat Protection, Memory Function - Image 3](https://m.media-amazon.com/images/I/71Mkn7UkltL.jpg) ![AquaMiracle Mini Aquarium Heater 20W Small Fish Tank Heater for 2-4 Gal Tanks, Digital Display Thermostat Betta Heater with Dry-Run & Overheat Protection, Memory Function - Image 4](https://m.media-amazon.com/images/I/71gSCn1ueRL.jpg) ![AquaMiracle Mini Aquarium Heater 20W Small Fish Tank Heater for 2-4 Gal Tanks, Digital Display Thermostat Betta Heater with Dry-Run & Overheat Protection, Memory Function - Image 5](https://m.media-amazon.com/images/I/71u2ZaPXmXL.jpg) ## Available Options This product comes in different **Size** options. ## Customer Reviews ### ⭐⭐⭐⭐⭐ Tiny yet mighty! *by L***G on October 21, 2023* Sam, our unexpected Betta fish birthday gift for our 7-year-old, quickly became a beloved member of our family. To ensure his happiness and comfort in his new home, we had to learn the ropes of Betta care. It was surprising to discover that these little fish, often sold in deli containers at pet stores, require a considerable amount of care. During our research, we learned that Betta fish thrive in water temperatures between 78 to 82 degrees Fahrenheit, and achieving this meant we needed 5 watts of heating power per gallon. That's why we found the 20-watt heater to be a perfect match for our 4-gallon tank.This compact heater was an ideal solution for our uniquely shaped round tank, where our only option was a fully submersible heater. Many other models we came across were bulky and had no suitable attachment points. However, this heater's strong suction cup allowed us to discreetly position it near the rim of the tank, preserving the tank's aesthetics. Not only has it maintained a consistent water temperature of a perfect 80 degrees, but it's also safe to touch, as Sam often swims close to it without harm.One feature we appreciate is the easily visible digital display, which helps us monitor the temperature and ensure Sam's safety. However, my one concern is the auto-shutoff setting, which is set at a rather high 97 degrees. Knowing that Bettas cannot survive in water temperatures exceeding 86 degrees, I can't help but worry about the possibility of returning home to an overheated tank. ### ⭐⭐⭐⭐⭐ Doing its job! *by E***H on December 15, 2024* The media could not be loaded. I absolutely love this little heater! It’s the perfect size for my betta tank, and it does exactly what it promises. The adjustable temperature feature is spot-on, and it holds the temperature consistently without any fluctuations. I was pleasantly surprised by how reliable it is for such a compact heater. It’s discreet, easy to install, and doesn’t take up much space in the tank. If you’re looking for an affordable and efficient heater for your betta or small aquarium, this is definitely the one! I’ve attached a video showing how well it works in my tank. ### ⭐⭐⭐⭐⭐ Great for a small tank *by J***A on July 3, 2025* Like the heater and the fish loves the heater but I wish the cord could bend a little more --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.us/products/461489991-aquamiracle-mini-aquarium-heater-20w-small-fish-tank-heater-2](https://www.desertcart.us/products/461489991-aquamiracle-mini-aquarium-heater-20w-small-fish-tank-heater-2) --- *Product available on Desertcart United States of America* *Store origin: US* *Last updated: 2026-05-22*