The heater

Since this will be a tropical aquarium, it will require heating.

Fish are poikilotherms, so (in rather crude terms), their environment affects their metabolism. Because fish are not able to regulate their own body temperature, the temperature of the water will affect their enzyme activity, so it is important that an appropriate water temperature, which is sustainable in the long term, is chosen for the fish to live in. This also means that temperature will affect the lifespan and activity level of the fish: for the same fish, a higher water temperature would mean more active fish with shorter life span, while a lower temperature would result in lower level of activity, but with a longer lifespan.

Changes in temperature throughout the year or during a rainy season can also be a breeding trigger for some species of fish. The latter can easily be simulated by large water changes with cool or cold water. Seasons of the year are more difficult, although still possible by setting the heater to a lower temperature in winter and increasing it toward summer, then lowering it again for the winter.

In fishkeeping, fish are usually divided into three groups:

Fish which live best at water temperatures of 1 – 16 °C, for example, common goldfish
15 – 22°C, fish such as fancy goldfish, white cloud mountain minnows and hillstream loaches
20 – 30 °C, which include some of the most popular aquarium fish, such as neon tetras and angels

There are, of course, plenty of fish which overlap two (or all) of these groups, or are even outside those temperature ranges altogether. Since there are almost no species of fish, available within the aquarium trade in Europe, which fit into either of the first two categories and a 60 litre aquarium, I have settled on tropical fish.

In an average European household, approximately 1 watt of heater per litre of aquarium water (rounded up, as needed) is enough to keep the water up to temperature when the temperature drops inside the house in winter. Because this is a small aquarium, I will be using the 50 W heater which was included in the set. For aquariums over 100 cm in length, I normally prefer to use more than one heater to make sure that the temperature is the same throughout.

Most heaters have inbuilt thermostats, so it should not matter if the chosen heater gives more than 1 watt per litre of water, but when a heater breaks, it is most often in the “on” state, which means that the heater does not switch off when the water is warm enough. Because of this, I prefer to use appropriately rated heaters, so it is more likely that I will have time to notice the problem, before the fish come to harm.

Internal heaters are usually made out of glass (sometimes with a removable plastic cage around them), polymers and metal. The most common heater are made of glass, but these can be cracked easily, so one has to be careful about letting them cool down properly before taking them out of water and large fish can break them. Polymer heaters are considerably more difficult to break, but are slightly more expensive and difficult to manufacture. Metal heaters are uncommon.

Another common problem with internal heaters is that the numbers on the temperature dial (or a separate scale on the heater itself) do not correspond to the temperature that the heater will be heating to, because these can easily become displaced. This is not a problem, as long as you know how high the displacement is.

On top of the standard internal heaters, one can now buy in-line heaters for external filters, external filter with heaters built into them and undergravel heaters.. but all of these are currently less common and none are suitable for the set-up which I am planning.

In addition to the heater, I will also buy a glass thermometer.

The filter

Filters are essential to modern fish keeping: they are home to bacteria which make the water safe for the fish.

The nitrogen cycle in an aquarium commences at the point where fish and dead plant matter produce ammonia. Some of the ammonia is then used up by plants, but the majority is converted, by bacteria which live in the filter, into nitrite. Nitrite is then converted by filter bacteria into nitrate. Some nitrate is used up by plants and the rest is removed during water changes.

The general format of a filter is some sort of pump which causes water to move through some media. This is usually in the form of an internal filter, an external filter, an air pump powered sponge filter, an undergravel filter, a sump, a trickle filter, a hang-on-the-back filter, and so on. For this aquarium, I will be using an internal filter, potentially moving onto an external later on.

There are three types of media usually used in filter:

Mechanical media:
This media includes various sponges, wool and floss, it physically removes dirt from the aquarium by not letting it pass through the filter.
Chemical media:
The primary function of this media is to adsorb undesirable certain molecules out of the water: for example, activated carbon can be used to remove the remainder of medication after a completed treatment. Some “chemical media” works on the basis of ion exchange. It should usually not be used on an every day basis.
Biological media:
Bio-media is the best media for the bacteria to live on because it is usually very porous, so has a high surface area. It is usually made out of some sort of ceramic material. In an undergravel filter, the bio-media is the gravel and in a sponge filter, it is the sponge.

The bacteria are not particularly picky, so will actually live on any surface they can, regardless of the type of media used.

The first step for setting up the aquarium will be cultivating these filter bacteria. They are present in tap water in very small numbers, so I will be feeding them ammonia to encourage the colony to grow. Once the colony is large enough to support fish life, I will be replacing the ammonia with fish (who naturally produce ammonia).


The filter which came with the kit is a Powerbio 700 by Classica (which is the Arcadia brand for non-lighting equipment). It consists of a standard filter power head with a screw-on spray bar attachment, on top of a filter media housing which contains a cage for loose media (containing carbon) and a rough black sponge (not carbon). The carbon has already been taken out and I will be replacing it with some form of bio-media. I will keep the carbon in case I ever need to remove medication after treatments.

The glass box

The aquarium

This log is about a pretty standard 60 litre aquarium (which is approximately 16 US gallons or 13 imperial gallons). It is a standard shape: 60 cm long, by 30 cm deep, by 36 cm high (which is approximately 24 × 12 × 14 inches). For the purpose of setting up and running an aquarium, the specific manufacturer of the glass doesn’t matter.

The three most common materials used for aquaria are glass, plastic and acrylic. I prefer glass because it does not scratch as easily as cheap plastic aquaria and acrylic is used predominantly for oddly shaped or large aquaria.

For simplicity and because I prefer aquariums with a flat front and curved corners, I decided to go for the Arc Tank II kit by Arcadia. It is an all-in-one package which contains most of the equipment needed to start.

The glass is 5 mm thick, with a slight green tinge. The silicone is clear, and the joints are quite neat, so it is barely visible. The surround on the bottom is a thin and made of metallic grey plastic. The aquarium itself is suspended on the frame, about 3 mm from the surface, with all the weight being spread between the four corners. The cover glass is 3 mm acrylic, with a large cut-out for the light fitting on the back a smaller cut-out for feeding on the front. Due to the thinness of the acrylic, it does sag in the centre. The cover glass is quite loose and is very light, so if one is planning to keep fish which are known for attempts to get out, a new cover glass will be required.

Because the aquarium is suspended on a frame, a base mat should not be used. For the same reason, whatever is used for the aquarium stand should provide good support in the corners as it will weigh 70-80 kg when full of water and decor.

Overall, it is nicer than the average aquarium with a lid and looks neat.