Do Guppy Fish Need a Heater: Reasons & Recommendations

Tropical fish in your home aquarium need a warm environment to thrive. But not all tropical fish will be suitable for this type of setup. Before you decide to get a guppy fish, it is important to know what they need, especially when it comes to their temperature requirement.

In this article, we are going to discuss if guppies need a heater as well as share some of the most common scenarios that can happen if their ideal temperature is not met.

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Do Guppies Need a Heater?

As tropical fish, guppies need a heater in their aquarium to achieve the comforts of a relatively warm temperature. Aside from a heater, it would also help if there were some plants around the water so that it gets filtered by them rather than just having open water for too long periods. There are times when tropical fish are kept at higher temperatures, but not for long periods.

Without a heater, tropical fish will be left with open water, which is not ideal for them to thrive. The only way to solve this problem is by adding a heater and some live plants around the tank so that they can have a more comfortable environment to live in.

What Temperature Do Guppies Need?

While the temperatures of your tank will depend on whether you have an aquarium heater installed or not, tropical species thrive at above 77 degrees Fahrenheit (25 degrees Celsius), which is correct in the case of guppies. The ideal temperature for guppies is between 74 degrees Fahrenheit to 82 degrees Fahrenheit (23 degrees Celsius to 28 degrees Celsius).

Where Should You Place The Heater?

Most aquarium heaters come with an adjustable thermostat, so you can place the device where it will do the most good for your tank. The downside is that if you’re using a horizontal or lateral-flow style heater and have more than one – especially if they’re placed close together in a large tank – some of the hot air may vent over the side onto your fish and plant life, potentially causing harm.

What Happens if the Water Gets Too Cold?

Guppies will tolerate a small drop in water temperature, but it is important to understand why they need the heater and what effect lowering their tank’s temp limit would have on them. In many tropical fish tanks, there are times when you’ll want to lower your guppies’ cold water limits by placing the heater dials below 78 degrees Fahrenheit during atypical dry weather months.

If the water in your aquarium drops to a temperature too low, do not panic. As long as you had been maintaining it at an average between 78 degrees Fahrenheit and 82 degrees Fahrenheit before this happened, there is no need for concern. However, you don’t want to prolong this cold temperature. Inadequate heater placement for a very long time can lead to an overall cooler water temperature, which in turn can stress your fish out and eventually, cause them to die.

What Happens if the Water Gets Too Hot?

If you don’t lower your water’s temperature either by lowering the heater or raising the wet-bulb thermometer reading to a more aggressive level (blue being neutral), your guppies can quickly overheat. While hobbyists are able to successfully keep their guppies in hot arid climates with few health issues as long as they have low lighting and plenty of hiding areas, guppies who live in tropical regions where sunlight levels become too high can become ill very quickly.

What Size Heater Should I Get?

Aquarium heaters are relatively inexpensive.  They come in all shapes and sizes, but the rule of thumb is to get as big a heater as you can afford/have space for while still having enough circulating room around it so that evaporation (the water level dropping resulting from a loss of heat) doesn’t cause “hot spots”.

There are a few factors to consider when purchasing a heater for your aquarium. The size of the heater and the wattage it generates. Here are some general guidelines:

  • If you have a smaller tank (under 20 gallons/75 liters), it is typically better to settle with 25 to 75-watt heaters.
  • If you have an average-size tank (20 gallons/75 liters to 40 gallons/150 liters), go for an electric heater that produces greater watts. Heaters with 150 to 300 watts will effectively heat up average-size tanks faster.
  • If you have a larger tank (50 gallons/200 liters to 75 gallons/300 liters), the smart choice is to go for heaters that produce 400 to 600 watts.

Of course, these estimations still depend on the required heating according to the room temperature where your fish tank is located.

Frequently Asked Questions (FAQ’s)

Q: How much does it cost to buy a heater and what’s included in the price?

A: Heaters can vary in price from $10 to $70, but they typically include some type of thermostat and cord reel.

Q: How do I know if my guppy fish need a heater?

A: Mainly, you can judge by looking at the fish’s behavior. If they are not spending most of their time outside in the open water and prefer to stay on a bed or hide under an object such as large rocks, small pieces of driftwood, or hardware cloth then this is probably a good indication that it would be for your best interest to get them one.

Q: Can guppies live without a heater?

A: This is a loaded question because there are different opinions on the matter. But, most of them say that they can live without one if they have enough hiding places and time spent underneath water objects such as driftwood or small rocks to keep their temperature constant. It’s not recommended however since guppies thrive when in warmer conditions so getting an aquarium heater is much more beneficial compared to keeping your guppy outside all day doing nothing but waiting for basking time.

Q: How cold can guppies survive?

A: In general, they can survive in temperatures as low as 60 degrees Fahrenheit (15 degrees Celsius).