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Helping Your Fish Cope with the Summer Heat

Helping your fish cope with the Summer heat

Just like us, our fish friends feel stressed when it’s extremely hot outside. Here are 10 ways you can help them stay cool and calm.

Why is Water Temperature Important?

Maintaining a stable water temperature within the recommended range for your fish is incredibly important for the health of your fish. When tank temperatures are high, the warm water causes your fish to become more active and require more oxygen. Just one problem – warm water holds less oxygen than cooler water. In severe cases, there won’t be enough oxygen to go around, and your fish can suffocate.

To add to the problem, the beneficial bacteria in your aquarium need oxygen to break down ammonia (waste toxin). Without enough oxygen to go around, the ammonia in your tank begins to build up, displacing oxygen and burning the gills of your fish. As you see, warm water can kick-start a number of deadly problems in your aquarium.

The ideal temperature range for a freshwater aquarium ultimately depends on the type of fish you have. To determine the right temperature for your aquarium, you may need to do some research on your particular fish species and their ideal temperature range. As a general guideline, tropical fish tanks should not go over 28 °C and goldfish tank temperature should range between 18-23°C.

To keep your fish cool and calm this summer, here are some simple tips to use when temperatures are extreme:

  1. Cool the water

If the aquarium water temperature is getting warmer on a hot day, you can float a bottle of ice or cold water in the fish tank to gently lower the water temperature. To prepare the bottle, simply freeze water in clean bottles that have never been exposed to soap or other detergents. Don’t use ice packs as they can leak, and don’t throw ice cubes directly into the water either.

Let the frozen or cold-water bottles float in the tank and take them out when the temperature hits the right level. Be sure to monitor the temperature – there’s no easy way to control how much or how quickly the temperature in the tank will drop. While reducing the temperature is important on especially hot days, it must not be done too quickly. Take care not to lower the temperature more than 1°C per hour. A sudden drastic drop in aquarium temperature can trigger the onset of ich or other parasites.

  1. Turn the heater down

For tropical fish tanks you can cool the water by turning your heater down, but don’t turn it off completely. We recommend that you leave the heater on and keep it plugged in – just in case the ambient temperature suddenly drops and you forget to plug it back in!

  1. Maintain oxygen levels

Good water circulation is key to keeping the water cool. Ensure that tanks are well aerated to maintain oxygen levels (the hotter the water, the less oxygen it can carry). Adding extra air lines in your tank will help to increase oxygen exchange.

Also check to ensure that filters are working properly, with adequate water flow. Without good circulation the water’s dissolved oxygen levels can become alarmingly low at higher tank temperatures.

  1. Check water parameters

Regular water testing ensures a healthy environment for your fish and is an important part of setting up your new or existing aquarium. Make sure water parameters, such as pH, ammonia and nitrate are correct.

  1. Close the curtains

If your aquarium is near a window, close the curtains to prevent direct sunlight from heating the water.

  1. Open the aquarium cover

Open the aquarium cover and position a fan to blow across the surface of the water. Make sure the fan is safety positioned and the cables out of the way. The circulation of air will blow heat away from the surface, but you may want to lower the water level an inch or two - to prevent fish from jumping out! Also when the lid of off, make sure that other pets (such as cats and dogs) cannot get their paws into the tank!

  1. Do not overstock

Be careful not to have too many fish in your tank. Overstocking tanks increases oxygen consumption, which in turn decreases oxygen levels. Overstocking also increases the amount of waste that your filter system has to cope with, which means it may not work as efficiently.

  1. Frequent water changes

More frequent water changes can help by reducing water temperature (if tap water is colder than the tank) and build-up of toxic metabolites. You can do this by performing small partial water changes with slightly cooler water, making sure not to drop the temperature of your aquarium too rapidly. Make sure to never change more than 25% of the water in one week.

  1. Adjust feeding

In warmer conditions, you should actually feed your fish more. While it does increase the production of waste which can dirty the water, fish burn off more energy in summer so they need the additional nutrients to fight off parasites and infections. Cutting down their food will reduce their immune system in warmer weather. Make sure to be more vigilant with your fish tank or pond maintenance in this time and once things cool off again you can resume your normal routine.

  1. Minimize lighting

Some aquarium lights can emit heat that will increase the temperature of your tank even further. On days of extreme heat, turn off your lights (if possible) – or in the case of planted and reef aquariums, limit the number of hours the light is on to help reduce heat generation.


Signs of stressed fish during hot weather

Rapid gill movement or gasping for air at the surface or at the bottom of the tank are the main signs of stress during hot weather. Algae growth may increase, and the water may begin to turn cloudy due to a bloom of heterotrophic bacteria. When your fish are overheated and stressed, their immune systems are compromised and they’re more likely to get sick.


Looking for fish care tips and advice?

Regardless of what methods you choose to prevent your fish tank from overheating, always remember to make any fish tank temperature changes in your aquarium gradual.

Contact Melbourne Tropical Fish for more information and advice on how to care for your fish.


Contact Us

Melbourne Tropical Fish

Factory 2/41-43 Sinclair Rd

Dandenong VIC 3175

(03) 9792 5513


1 comment

  • thank you :)


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