For those who nostalgically recall childhood and days when they got their first PC, I am going to tell the story of an idea which was done as a school project by my students…
One day, while watching a screen saver that showed a flock of fish, I told my pupils that I would like to have a real aquarium in the screen. How would that be possible, they asked. Easily, I said, as we just needed to find an old PC monitor and replace the screen glass with a water tank. That would also be a challenge for all of us to explore the biological and chemical aspects of dealing with living conditions in aquariums.
After the first brainstorming and after dividing pupils into working groups, we soon collected many interesting pieces of information from the Internet, such as the epochal discovery in aquatics history where scientists found out water plants give oxygen to fish to breathe (Joseph Priestley, 1774) and that the first aquariums originated in China 3000 years ago… It is believed that goldfish were introduced from east Asia to Portugal in 1611 and from there to other parts of Europe… Some student groups explored theories concerning the construction of a water tank which would enable our goldfish survival in a small computer monitor’s water tank.
Water is the medium fish need to live, in the same way people need clean and fresh air. In nature, it is impossible to find perfectly clean water. The chemical composition of water is changed from the very moment a ground spot is touched by rain depending on the area water passes through. Plants and fish from different areas are accommodated to the chemical composition of water in their climate. Fortunately, most of the fish we usually buy in pet shops have been accommodated to the chemical composition of water in our environment, including the goldfish we wanted to pick up for our project. So I told my pupils to consider the chemical conditions of water firstly, such as water hardness.
Abrupt changes endanger fish lives
Water hardness measures dissolved mineral content in water. There are two types of water hardness which should match the natural habitat of our fish: General hardness (GH) and Carbonate hardness (CA).
General hardness (GH) relates to the ratio of carbonate and non-carbonate hardness. It is mostly determinated by the amount of calcium (Ca++) and magnesium (Mg++) salts. It is expressed by the content of calcium carbonate (CaCO3) and it is measured in degrees of hardness (DH). Mark ppm indicates the amount „per million“, which is the equivalent for mg/Liter of water. 1 DH equalls to 17.8 ppm of CaCO3, easier to understand according to the following table:
|0-4 DH||0-70 ppm||very soft water|
|4-8 DH||70-140 ppm||soft water|
|8-12 DH||140-210 ppm||medium hard|
|12-18 DH||210-320 ppm||hard water|
|18-30 DH||320-530 ppm||very hard water|
Luckily, the test kit we bought and used in our project included everything we needed for measuring the general and carbonate hardness of our aquarium water as well as everything needed for detecting any low carbonate hardness levels, which generally lead to rapid and wide pH shifts. Abrupt changes in water can be very harmful to aquatic life.
Water plants and other tips
A planted fish tank brings a true look of an aquatic environment. Plants require some special help to keep them alive, but they will contribute to a realistic ecosystem as carbon dioxide is transformed into oxygen just like with trees. A few great tips for keeping plants alive are as it follows:
- Consider that goldfish eat the greenery and devour it, too!
- Once rooted, it is better not to move the plants.
- Plants need extra light. We should also use a bulb made for enhancing the growth of plants.
- We should regularly pinch off faded and discoloured stalks. Just as in a backyard garden, underwater species also require pruning to keep them healthy and allow the roots to generate new stalks to replace old ones.
- Another way to control algae growth is to have several plants.
Attention needs to be given to the location of the aquarium, too. This should be done before setting it. When choosing the best place, it is best to keep the following points in mind:
- Avoid direct sunlight which will raise water temperature and cause algae blooms.
- The classroom may not be the best place – an air pump and filter are noisy in a quiet room, but the pump doesn’t need to be plugged in all the time. It seems that fish like the periods of silence, too.
- Consider the weight of a filled aquarium. Glass cannot tolerate uneven weight variance so we used to check by level the screen stand to make a proper aquarium stand. Once, when it is set, it should not be moved any more.
And some more tips…
- Do not overfeed the fish. Fish do best when fed 5 days a week. A few days without food is good for their metabolism anyway. Furthermore, a fully cycled tank offers a continuous supply of edible microscopic particles so it is highly unlikely that fish starve.
- Fill the aquarium 3/4 full with lukewarm tap water.
- To remove dust, if using rocks from outdoors, soak them in a bucket of water for at least a day because dust is accumulated within its pores and requires a long soak to completely dissolve. We suggest only using aquarium approved ornaments as other can leak toxins into the water.
How we constructed the aquarium step by step
- Making the proper water tank needed precise measuring, which we did by ourselves, though the gluing was entrusted to a professional glazier who had experience in water tanks construction.
- We dismantled the monitor and installed an electric light bulb in the background of the housing.
- The electricity supply was conducted by an electric cable to the mouse, which was redesigned into a power switch.
The whole class was overwhelmed with great excitement when the work was brought to the end, and we could hardly wait the moment when we put our fish into the tank. Everything worked perfectly after the fish came. We were very happy to see them alive for a long time after they got used to their new home.
Article written by: Milorad Vučković, Scientix Ambassador