In the previous article we had a look at some of the reasons why fish need to have their water kept at certain temperatures in an aquarium.

The next important thing about temperature to be aware of is keeping your aquarium’s temperature stable. Parameters in the environment particularly in the ocean do not fluctuate very much. Most changes that do occur do so only very slowly over time. What does this mean for our aquariums? It means that we have to ensure that the temperature of the water is not only within the suitable range for the fish we are keeping but that it must not move outside of that range especially not quickly.

If your house is not stable in terms of temperature then you need to take extra measures to keep your tank at a stable temperature. If the room the aquarium is kept in gets hot in summer, cold in winter, or cold over night because it isn’t heated or air-conditioned you might need to check how hot or cold your aquarium is getting.

You will always need a thermometer to measure the temperature of your tank anyway, however it will be necessary to make sure that there is not a great deal of variation. In some countries this will be a bigger problem then others.

In many countries where it is very cold in the winters the houses are heated centrally and so the house is kept at a fairly constant temperature during winter. Similarly in summer the use of air-conditioning will reduce the occurrence of this problem.

This isn’t to say that you need to go and heat or air condition your house to keep fish. What you need depending on what temperature changes you may encounter is a heater, or a chiller or both. Heaters will prevent your water from getting too cold overnight. This can happen in unheated tanks often at the end of autumn winter and spring where it can be mild or warm during the day through the ambient temperature, but the temperature may drop at night. This is especially true in smaller tanks where the water is more prone to cooling.

The reverse is true in summer especially in tropical tanks where you have heating but the outside temperature is warmer than the tank heating the tank up further. You can purchase a chiller which works in a similar manner to refrigerators. Water is passed through the chiller via a pump and the water is cooled. However they do tend to be expensive and noisy. The cheaper alternative is to get some plastic soft drink bottles and fill them with water and freeze them.

When it gets hot, throw them in, just have a few cycling between the freezer and your tank. The bonus of this is as the ice melts if you loosen the top of the bottles a little the fresh water will add to the tank water which will have lost some of its volume through evaporation.

Back to Temperature Guide Part 1

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