10 Best Freshwater Aquarium Heaters & Thermometers 2025: According to Reviews | Chewy

The 10 Best Freshwater Aquarium Heaters & Thermometers

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How we created this freshwater aquarium heaters & thermometer list

We leveraged input from our veterinarians and artificial intelligence to identify key considerations to help you find the best freshwater aquarium heaters & thermometer.
We scanned thousands of customer reviews and ratings and scored each product based on its performance against each of the key considerations. We then considered how popular a product is with Chewy customers and combined that with its key consideration scores to create the list of the best freshwater aquarium heaters & thermometers.

Key freshwater aquarium heaters & thermometer considerations

Durability

Heating Capacity

Safety Features

Temperature Control

1
LvLrister Titanium Thermostat with Intelligent LED Display Submersible Aquarium Heater, 12.8-in, 300-watt
LvLrister Titanium Thermostat with Intelligent LED Display Submersible Aquarium Heater, 12.8-in, 300-watt
LvLrister Titanium Thermostat with Intelligent LED Display Submersible Aquarium Heater, 12.8-in, 300-watt
LvLrister Titanium Thermostat with Intelligent LED Display Submersible Aquarium Heater, 12.8-in, 300-watt
LvLrister Titanium Thermostat with Intelligent LED Display Submersible Aquarium Heater, 12.8-in, 300-watt
LvLrister Titanium Thermostat with Intelligent LED Display Submersible Aquarium Heater, 12.8-in, 300-watt
LvLrister Titanium Thermostat with Intelligent LED Display Submersible Aquarium Heater, 12.8-in, 300-watt
LvLrister Titanium Thermostat with Intelligent LED Display Submersible Aquarium Heater, 12.8-in, 300-watt
LvLrister Titanium Thermostat with Intelligent LED Display Submersible Aquarium Heater, 12.8-in, 300-watt

LvLrister Titanium Thermostat with Intelligent LED Display Submersible Aquarium Heater, 12.8-in, 300-watt

Rated 4.6 out of 5 stars
74
$23.99Chewy Price
Promo, New Customers Only: Spend $49+, Get $20 eGift Card

Our ratings

Durability

4.6/5
Excellent

Heating Capacity

4.6/5
Excellent

Safety Features

4.6/5
Excellent

Temperature Control

4.7/5
Excellent

Is this freshwater aquarium heaters & thermometer right for my pet?

Material

Plastic

Aquarium Type

Saltwater

Capacity (Max)

≥120-250-L

Fish Type

Tropical Freshwater
2
Fluval Electronic Aquarium Heater, 300-watt
Fluval Electronic Aquarium Heater, 300-watt
Fluval Electronic Aquarium Heater, 300-watt
Fluval Electronic Aquarium Heater, 300-watt
Fluval Electronic Aquarium Heater, 300-watt
Fluval Electronic Aquarium Heater, 300-watt
Fluval Electronic Aquarium Heater, 300-watt
Fluval Electronic Aquarium Heater, 300-watt
Fluval Electronic Aquarium Heater, 300-watt

Fluval Electronic Aquarium Heater, 300-watt

Rated 4 out of 5 stars
79
$39.75Chewy Price
Promo, New Customers Only: Spend $49+, Get $20 eGift Card

Our ratings

Durability

4.7/5
Excellent

Heating Capacity

4.8/5
Excellent

Safety Features

4.8/5
Excellent

Temperature Control

4.8/5
Excellent

Is this freshwater aquarium heaters & thermometer right for my pet?

Material

Plastic

Aquarium Type

Freshwater, Saltwater

Fish Type

Tropical Freshwater, Marine Fish
3
Underwater Treasures Floating Glass Fish Thermometer

Underwater Treasures Floating Glass Fish Thermometer

Rated 4.4 out of 5 stars
172
$1.75Chewy Price
Promo, New Customers Only: Spend $49+, Get $20 eGift Card

Our ratings

Durability

4.2/5
Great

Heating Capacity

4.3/5
Great

Safety Features

4.2/5
Great

Temperature Control

4.2/5
Great

Is this freshwater aquarium heaters & thermometer right for my pet?

Aquarium Type

Freshwater, Saltwater

Fish Type

Tropical Freshwater, Marine Invertebrate, Betta, Bottom Feeder...
4
Eheim Jager Thermostat Aquarium Heater, 50-watt
Eheim Jager Thermostat Aquarium Heater, 50-watt

Eheim Jager Thermostat Aquarium Heater, 50-watt

Rated 4.2 out of 5 stars
152
$22.94Chewy Price
Promo, New Customers Only: Spend $49+, Get $20 eGift Card

Our ratings

Durability

4.3/5
Great

Heating Capacity

4.3/5
Great

Safety Features

4.3/5
Great

Temperature Control

4.2/5
Great

Is this freshwater aquarium heaters & thermometer right for my pet?

Material

Plastic

Aquarium Type

Freshwater, Saltwater

Fish Type

Tropical Freshwater
5
SunGrow Betta & Turtle Submersible Aquarium Tank Water Heater with Thermostat, 10-watt, up to 5-gal
SunGrow Betta & Turtle Submersible Aquarium Tank Water Heater with Thermostat, 10-watt, up to 5-gal
SunGrow Betta & Turtle Submersible Aquarium Tank Water Heater with Thermostat, 10-watt, up to 5-gal
SunGrow Betta & Turtle Submersible Aquarium Tank Water Heater with Thermostat, 10-watt, up to 5-gal
SunGrow Betta & Turtle Submersible Aquarium Tank Water Heater with Thermostat, 10-watt, up to 5-gal
SunGrow Betta & Turtle Submersible Aquarium Tank Water Heater with Thermostat, 10-watt, up to 5-gal

SunGrow Betta & Turtle Submersible Aquarium Tank Water Heater with Thermostat, 10-watt, up to 5-gal

Rated 4.2 out of 5 stars
141
$10.91Chewy Price
Promo, New Customers Only: Spend $49+, Get $20 eGift Card

Our ratings

Durability

3.8/5
Good

Heating Capacity

4.2/5
Great

Safety Features

3.9/5
Good

Temperature Control

4.1/5
Great

Is this freshwater aquarium heaters & thermometer right for my pet?

Material

Plastic

Aquarium Type

Nano Tank, Freshwater

Fish Type

Betta, Tropical Freshwater, Goldfish, Cichlid
6
Penn-Plax Cascade Heat Preset Submersible Aquarium Heater, 10-in, 150-watt
Penn-Plax Cascade Heat Preset Submersible Aquarium Heater, 10-in, 150-watt
Penn-Plax Cascade Heat Preset Submersible Aquarium Heater, 10-in, 150-watt
Penn-Plax Cascade Heat Preset Submersible Aquarium Heater, 10-in, 150-watt
Penn-Plax Cascade Heat Preset Submersible Aquarium Heater, 10-in, 150-watt
Penn-Plax Cascade Heat Preset Submersible Aquarium Heater, 10-in, 150-watt
Penn-Plax Cascade Heat Preset Submersible Aquarium Heater, 10-in, 150-watt
Penn-Plax Cascade Heat Preset Submersible Aquarium Heater, 10-in, 150-watt
Penn-Plax Cascade Heat Preset Submersible Aquarium Heater, 10-in, 150-watt

Penn-Plax Cascade Heat Preset Submersible Aquarium Heater, 10-in, 150-watt

Rated 4.3 out of 5 stars
69
$16.39Chewy Price
Promo, New Customers Only: Spend $49+, Get $20 eGift Card

Our ratings

Durability

3.6/5
Good

Heating Capacity

4.0/5
Great

Safety Features

3.8/5
Good

Temperature Control

4.2/5
Great

Is this freshwater aquarium heaters & thermometer right for my pet?

Material

Plastic

Aquarium Type

Freshwater

Fish Type

Tropical Freshwater
7
Cobalt Aquatics Electronic Neo-Therm Pro Submersible Aquarium Heater, 50-Watt
Cobalt Aquatics Electronic Neo-Therm Pro Submersible Aquarium Heater, 50-Watt
Cobalt Aquatics Electronic Neo-Therm Pro Submersible Aquarium Heater, 50-Watt
Cobalt Aquatics Electronic Neo-Therm Pro Submersible Aquarium Heater, 50-Watt
Cobalt Aquatics Electronic Neo-Therm Pro Submersible Aquarium Heater, 50-Watt
Cobalt Aquatics Electronic Neo-Therm Pro Submersible Aquarium Heater, 50-Watt

Cobalt Aquatics Electronic Neo-Therm Pro Submersible Aquarium Heater, 50-Watt

Rated 4.1 out of 5 stars
54
$55.48Chewy Price
Promo, New Customers Only: Spend $49+, Get $20 eGift Card

Our ratings

Durability

4.1/5
Great

Heating Capacity

4.2/5
Great

Safety Features

4.4/5
Great

Temperature Control

4.3/5
Great

Is this freshwater aquarium heaters & thermometer right for my pet?

Material

Plastic

Aquarium Type

Freshwater, Saltwater

Fish Type

Marine Fish, Tropical Freshwater
8
Marina Floating Thermometer with Suction Cup for Aquariums

Marina Floating Thermometer with Suction Cup for Aquariums

Rated 4 out of 5 stars
239
$3.19Chewy Price
Promo, New Customers Only: Spend $49+, Get $20 eGift Card

Our ratings

Durability

3.8/5
Good

Heating Capacity

4.0/5
Great

Safety Features

4.0/5
Great

Temperature Control

4.0/5
Great

Is this freshwater aquarium heaters & thermometer right for my pet?

Material

Plastic

Aquarium Type

Freshwater, Saltwater

Fish Type

Tropical Freshwater, Marine Fish
9
OASE Indoor Aquatics Biomaster Thermo 350 External Fish Heater
OASE Indoor Aquatics Biomaster Thermo 350 External Fish Heater
OASE Indoor Aquatics Biomaster Thermo 350 External Fish Heater
OASE Indoor Aquatics Biomaster Thermo 350 External Fish Heater
OASE Indoor Aquatics Biomaster Thermo 350 External Fish Heater
OASE Indoor Aquatics Biomaster Thermo 350 External Fish Heater
OASE Indoor Aquatics Biomaster Thermo 350 External Fish Heater
OASE Indoor Aquatics Biomaster Thermo 350 External Fish Heater
OASE Indoor Aquatics Biomaster Thermo 350 External Fish Heater

OASE Indoor Aquatics Biomaster Thermo 350 External Fish Heater

Rated 4.7 out of 5 stars
18
$319.99Chewy Price
Promo, New Customers Only: Spend $49+, Get $20 eGift Card

Our ratings

Durability

4.7/5
Excellent

Heating Capacity

4.4/5
Great

Safety Features

4.7/5
Excellent

Temperature Control

4.3/5
Great

Is this freshwater aquarium heaters & thermometer right for my pet?

Material

Plastic

Aquarium Type

Freshwater

Fish Type

Tropical Freshwater
10
SunGrow Betta Fish Thermometer Sticker, Temperature Strip for Small Aquarium & Reptiles Tank
SunGrow Betta Fish Thermometer Sticker, Temperature Strip for Small Aquarium & Reptiles Tank
SunGrow Betta Fish Thermometer Sticker, Temperature Strip for Small Aquarium & Reptiles Tank
SunGrow Betta Fish Thermometer Sticker, Temperature Strip for Small Aquarium & Reptiles Tank
SunGrow Betta Fish Thermometer Sticker, Temperature Strip for Small Aquarium & Reptiles Tank
SunGrow Betta Fish Thermometer Sticker, Temperature Strip for Small Aquarium & Reptiles Tank
SunGrow Betta Fish Thermometer Sticker, Temperature Strip for Small Aquarium & Reptiles Tank

SunGrow Betta Fish Thermometer Sticker, Temperature Strip for Small Aquarium & Reptiles Tank

Rated 4 out of 5 stars
72
$1.99Chewy Price
Promo, New Customers Only: Spend $49+, Get $20 eGift Card

Our ratings

Durability

3.9/5
Good

Heating Capacity

4.2/5
Great

Safety Features

4.3/5
Great

Temperature Control

4.2/5
Great

Is this freshwater aquarium heaters & thermometer right for my pet?

Material

Plastic

Aquarium Type

Nano Tank, Freshwater, Saltwater

Fish Type

Betta, Goldfish, Cichlid, Tropical Freshwater...