How to make a mini aquarium

12 Feb 2013
Alex Walker


This tiny tank is its own complete ecosystem: it doesn't need a filter or frequent cleaning.

1. Prepare the tank

Take a jar with a lid and poke an air hole in the cover. Cover the bottom with big and small stones to grow beneficial, faeces-degrading bacteria and give shy fish a place to hide.

2. Pour in the water

Add water. If you're using chlorinated tap water, let it sit a while until the fumes evaporate. Once a month replace half the water and wipe off algae as needed.

3. Plant a few weeds

Live aquatic greenery keeps the water oxygenated, and it also uses the nutrients extracted from fish faeces. One sprig will be enough for such a small space.

4. Release the fish

Choose breeds that grow no longer than 4cm. Minnows are hardy, but guppies, neon tetras or zebra danios work well too. Two or three are plenty. Even one will be quite happy.

5. Add some snails

Snails keep the tank clean by eating algae. Pet shops often have them in their tanks -- ask the staff to throw in a few with a plant for free, the smaller the better (5mm, tops).

6. Feed your new friends

Be sparing. A small tub of goldfish food flakes will last several months. Dip the wet end of a toothpick into the fish food and swish it in the tank until the bits float off.