Aquarium Heaters

Top 5 30 Gallon Fish Tank Heater: Buyer’s Guide (2025)

Featured Image 30 gallon fish tank heater

For many fish enthusiasts, especially those with freshwater or saltwater species, an aquarium heater is a crucial piece of equipment. Fish, similar to turtles, cannot produce their own body heat. Consequently, they rely on the temperature of the water to avoid becoming too cold or overheated.

Article Summary

  • An aquarium heater is essential for maintaining the right temperature for fish in freshwater or marine tanks, as fish rely on the water temperature to regulate their body heat.
  • Different types of aquarium heaters, including hanging, substrate, submersible, inline, and filter heaters are available options.
  • To determine the right heater size, it’s generally recommended to use 2.5 to 5 watts per gallon of water.

Aquarium heaters do just that. They increase and maintain the temperature of your aquarium water to keep your tank’s inhabitants comfortable and healthy. However, not all heaters are created equal, and there are important considerations you need to take into account before selecting a unit.

To help you find the best 30 gallon fish tank heater, I’ve reviewed a variety of products that are suitable and, most importantly, effective for aquariums of this size.

After considering all the options our top picks were…

Review Summary

Out of all the aquarium heaters I’ve reviewed, this unit is my top recommendation for your aquarium.

Fluval’s submersible heating device is a great pick for your aquarium as it has a wattage of 150 W. It keeps your aquarium at a consistent temperature and has safety features like a bumper guard.

If you want a decent but affordable 30 gallon fish tank heater, this one is a good option.

This Tetra preset heating device is inexpensive but keeps your aquarium water at a stable temperature. It’s easy to install and has a light that indicates when the unit is turned on or off.

My personal favorite heating device. It’s a little pricier than some of the other units, but it comes with a lot of features.

Types of Aquarium Heaters

There are a variety of fish tank heaters you can use in your 30 gallon aquarium. They all have the same purpose (i.e, heat your aquarium water), but some types are a better pick for certain species of fish. However, most of it comes down to personal preference.

Hanging/Immersible Heater

A hanging/immersible heater goes over the top of your aquarium. The heating element of the device is positioned inside your aquarium to raise the water temperature. This type of heater requires you to have an opening in your aquarium hood, otherwise it won’t fit!

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Hanging heaters are commonly included in aquarium starter kits. They’re not as effective as some other varieties of heaters and aren’t the best option for brackish or saltwater tanks.

Substrate Heater

A substrate heater is typically used with a second heating unit. They consist of a long heating wire that is attached to the base of your aquarium.

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Substrate heaters are an ideal choice for tanks with live aquatic plants as they promote plant growth by increasing the water movement in the substrate. Unfortunately, substrate heaters are not very common, so they can be a bit on the costly side.

Submersible Heater

A submersible heater goes directly in your aquarium water, typically next to your filter. They are enclosed in a strong plastic or glass tube, with a coiled heating component inside. 

NOTE

Glass submersible heaters are prone to shattering if they overheat, so it’s important to monitor them closely. A heater can crack or overheat if taken out of the tank water without being switched off first.

Inline Heater 

An inline heater is placed on the outflow line of your filter so it can warm up the water pumped back into your fish. They’re a popular choice for aquarists who own big aggressive species of fish.

Filter Heater

Some filters have a heater built into them. This lets the heater instantly warm up the water that the filter pumps back into the aquarium. You can find filter heaters in some types of power or canister filters. 

30 Gallon Aquarium
30 Gallon Aquarium

What Size Heater Do I Need for a 30 Gallon Tank?

Using the right size heater for the capacity of your aquarium is important for optimal effectiveness. If the unit you use doesn’t have a high enough wattage, then it will struggle to heat your aquarium at an appropriate temperature.

NOTE

It’s generally recommended to use 2.5 to 5 watts per gallon of water. So, for a 30-gallon aquarium, you’ll need a heating device with a wattage of 75 W to 150 W.

Do Heaters Use a Lot of Electricity?

Your electricity provider, the size of your aquarium, and the wattage of your heater all influence how much electricity your heater uses…

Take a look at the back of your heater to find out its wattage and multiply the wattage by the amount of hours it is turned on for each day. Next, multiply this number by the number of days in the current month, and divide this total by 1,000 to work out the overall kilowatts. 

For example, if you own a 100-watt aquarium heater that is turned on for 24 hours each day in a 31-day month, it will use around 74.4 kilowatts. If your electricity provider charges 10 cents per kilowatt hour, then your heater should cost around 7.44 dollars to run each month. 

How Long Does It Take to Heat a 30 Gallon Aquarium?

The length of time it takes for your heater to warm up your 30 gallon fish tank depends on the wattage of your unit and the temperature of the room your aquarium is located in. From personal experience, an aquarium heater normally takes around 24 hours to warm up the water in a 30 gallon tank.

Where Should an Aquarium Heater Be Placed?

Where you place an aquarium heater depends on the type you own. For example, inline heaters have a heating wire that needs to be attached to the base of your aquarium, while a submersible heater needs to go directly in your tank water.

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If possible, try to position your heater close to your filter so it can quickly warm up water that is pumped back into your tank. 

Aquarium Water Bubbles
Aquarium Water Bubbles

How Do I Know If My Aquarium Heater Is Working?

Knowing when your aquarium heater is functioning properly is crucial for ensuring the safety of your fish. If your heater overheats, then your fish are at risk of becoming too hot. In contrast, if your heater stops working altogether, then your fish will become too cold.

use an aquarium thermometer to check if your water temperature drops or rises. This lets you know if there is a fault with your heater…

To ensure neither of these issues happens to you, it’s a good idea to use an aquarium thermometer to check if your water temperature drops or rises. This lets you know if there is a fault with your heater.

A lot of the time when things go wrong in an aquarium, time is of the essence. If your aquarium water is too warm or cool, then you’ll need to act fast to rectify the situation.

NOTE

By using an aquarium thermometer, you’ll always be aware of your tank’s temperature, allowing you to intervene swiftly if something does go wrong. In addition to this, you should frequently check your heater to look for any signs of damage.

Best 30 Gallon Aquarium Heaters Reviews

The Fluval Marina submersible heater is an excellent option for most fish tanks. It keeps your aquarium at a consistent warmth to prevent temperature fluctuations.

an excellent option for most fish tanks. It keeps your aquarium at a consistent warmth…

The unit is 150 watts, so it shouldn’t have any issue heating fish tanks up to 40 gallons. It has an easy-to access temperature control knob for convenience, as well as an on/off light indicator to let you know when the device is working. For added safety, the heater includes a bumper guard to help protect your fish if they touch the device.

Easy to Install

The unit includes suction cups and a mounting bracket for quick installation. It’s made from impact-resistant glass with a waterproof sealing to increase durability of the device.

However, this heater does have a couple of issues. The mounting bracket included with the unit can be a little flimsy, which can make it difficult to attach the heater to your aquarium.

In addition to this, the temperature dial doesn’t include any markings other than plus and minus signs. This can make setting an exact temperature a bit hard.

This aquarium heating unit is an affordable but solid choice for your aquarium as it’s 100 watts. It has a built-in electronic thermostat which maintains your water temperature at 78°F, which is adequate for most tropical fish.

has a built-in electronic thermostat which maintains your water temperature at 78°F, which is adequate for most tropical fish…

For easy installation, you can place the device either horizontally or vertically using the provided suction cups. There’s also an indicator lamp on the unit that notifies you when the heater is switched on.

Temperature Indicator

When the LED light on the indicator is red, it means the device is actively heating. The light will then turn green when the correct temperature has been met. I really like this feature as you can clearly see at a glance ifk the device is functioning properly.

Compact Design

My favorite feature of this heating unit is its sleek and compact design. It has a small footprint which allows you to easily conceal it behind plants and other decor in your aquarium.

Despite its positives, there are a few minor problems with Tetra HT 100-watt heating units. They can sometimes struggle to keep your aquarium at a consistent temperature. The indicator light and the device itself can also break prematurely.

Hyffer’s submersible heating unit has a wattage of 100 W, so it’s a fantastic option for fish tanks, including saltwater tanks. Its temperature can be adjusted from 75°F to 91°F, which is ideal for most tropical species. 

a fantastic option for fish tanks, including saltwater tanks. Its temperature can be adjusted from 75°F to 91°F, which is ideal for most tropical species… 

Safety Features

I really like the safety features on this device. It will shut off when the desired temperature has been reached or if a fault with the unit occurs. It also includes a shield guard to help protect your tank’s inhabitants if they touch the device.

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You can also keep an eye on the temperature of your aquarium using the built-in thermometer. The temperature controls can also be accessed via an external remote, which is a nice touch.

Compact Design

This heating device has a compact design, so it’s very easy to hide it behind plants or other aquarium decorations. 

However, there are a couple of downsides of the device. The LED display on the external remote can be unreliable, as can the unit itself. This can cause the device to have a fairly short lifespan.

Aqueon’s submersible heater is another affordable but decent choice for your tank. It’s 100-watts and has precise temperature settings from 68 °F to 88 °F.

made from shatter-resistant glass and features an LED light that notifies you when your aquarium is being heated…

The device is made from shatter-resistant glass and features an LED light that notifies you when your aquarium is being heated. For safety, the unit automatically turns off if not fully submerged in your aquarium.

While this heater is an adequate option if you’re on a budget, it can be prone to rusting and overheating.

This heating device has a power of 200 watts, so it’s a little strong for aquariums that are only 30 gallons. However, it’s still worth considering, especially if you plan on upgrading to a bigger aquarium at some point.

made from high-quality quartz glass, has adjustable temperature controls from 68 °F to 93 °F…

The unit is made from high-quality quartz glass, has adjustable temperature controls from 68 °F to 93 °F and sports a visible temperature readout. This helps prevent temperature fluctuations to prevent your aquarium from becoming too hot or cold.

Easy to Install

The device is easy to install thanks to its strong suction cups, which keep the device firmly in place. It has a ceramic heating element to effectively maintain the warmth of your aquarium, as well as a light that indicates when the device is turned on or off.

Unfortunately, there have been a few reports of the heater having a fairly short lifespan and stopping working prematurely. 

Summary

Let’s take a quick look at all our top picks…

Best All-Rounder

Out of all the heaters I’ve looked at, I think the best one to use in your aquarium is the Fluval Marina Submersible Heater. It’s 150 watts, so it shouldn’t have any issue keeping your aquarium at a stable temperature.

The device features an easy-to-access temperature control knob, an on/off indicator lamp, and a bumper guard to help protect your tank’s inhabitants if they touch the unit.

Easy to Install

I like that the device is simple to install and is made from impact-resistant glass with a waterproof sealing. This makes the unit a lot more durable and robust. However, the heating device can be a bit hard to attach to your aquarium. Its temperature dial can also be a little difficult to use as it doesn’t have a temperature readout.

Other Great Options

If Fluval’s heating device doesn’t look like the right match for your aquarium, then I also recommend either the Tetra HT Submersible Aquarium Heating Unit or the Hygger Submersible Aquarium Heating Device. The former is extremely affordable, while the latter is a little more pricey as it has a range of features,

Best on a Budget

Tetra’s heating unit is preset to 78 °F, which is plenty warm enough for most fish species. It has an LED light that lets you know when the heater is actively heating or when the correct temperature has been reached. It also has a compact design to make it easy to conceal.

However, the device can sometimes struggle to keep your aquarium consistently warm. It can also break prematurely.

Editor’s Choice

Hygger’s heating device is 100 watts and has a range of safety features, including a shield guard. It has adjustable temperature controls that can be accessed via an external remote, which is a nice detail. Unfortunately, the external remote can be a little unreliable, and the device itself can have a short lifespan.