Hygger Aquarium Cooling Fan HG051 | Adjustable 2-Fan Tank Cooler

The Hygger HG051 Aquarium Cooling Fan is a clamp-on, dual-head cooling fan that drops aquarium temperature 2–4°F via surface evaporative airflow — perfect for summer heatwaves, high-output LED tanks, or any reef or planted aquarium that runs warmer than you'd like.

Pair it with a reliable heater and thermometer from our Maintenance & Water Care collection to keep your tank's temperature dialed in year-round.

Why an Aquarium Cooling Fan?

• Drops temperature 2–4°F through evaporative cooling — no expensive inline chiller required.
• Dual adjustable fans let you angle airflow exactly where it's needed across the water surface.
• Clamp-on installation mounts to most aquarium rims without tools.
• Quiet operation keeps the tank space livable, even in a bedroom or office.
• Multi-speed control lets you tune cooling vs. evaporation rate to your tank.

How to Use

• Clamp the fan to the rim of your aquarium with the airflow directed across (not down into) the water surface.
• Power on via included adapter and select a speed setting appropriate for the current tank temperature.
• Top off evaporated water daily — evaporative cooling means the tank will lose more water than usual. Keep an auto top-off (ATO) or watering can ready.
• Monitor with a thermometer and pair with a heater so your tank doesn't swing too cold overnight when ambient temperature drops.

Specifications

Recommended Pairings

• Eheim Jäger 125W Heater — classic glass submersible heater to balance overnight cooling
• IceCap 50W Titanium Heater — saltwater-safe titanium heater element
• Aquatop Pisces 25W Heater — preset nano-tank heater
• Browse all maintenance & water care

When You Need a Cooling Fan

• Reef tanks with high-output LEDs — bright reef lighting adds noticeable heat to the water.
• Planted tanks with strong PAR fixtures — same problem, freshwater edition.
• Summer temperature spikes — especially in rooms without strong AC.
• Sensitive species — coldwater fish, certain wild-caught species, and most corals prefer stable temperatures below 80°F.

Frequently Asked Questions

How much will this actually cool my tank?
Most setups see a 2–4°F drop depending on humidity, fan speed, surface area, and how open your tank's lid is. Open-top tanks see the biggest effect; closed glass lids reduce evaporation and cooling.

Do I have to remove the glass lid?
For best results, yes — or replace it with a screen/mesh lid. The fan cools by promoting evaporation, which requires open water surface.

Will it cause excessive evaporation?
You will see noticeably more evaporation when the fan is running. Top off with RO/DI (saltwater) or dechlorinated freshwater daily. An auto top-off (ATO) makes this effortless.

Can I use it overnight?
Yes, but consider pairing with a heater to prevent overnight temperature swings when ambient room temperature drops. A thermostat or smart plug can switch the fan off below a target temperature.

Freshwater and saltwater safe?
Yes — the fan does not contact tank water, only blows ambient air across the surface, so it's safe for both freshwater and saltwater (including reef) systems.