An aquarium will need, after all, some maintenance. At least every two weeks you should change some of the water, vacuum the gravel, and clean the equipment.

Do not use soap to clean anything that is going to be put in the fish tank. Soap is damaging to the sensitive tissue that forms the fish's gills.

Water changes

By changing some of the water in the aquarium, you are diluting nitrates and other mildly toxic substances, thus keeping them from building up in the fish tank.

It is important to say that you should never change all the water in the aquarium in a single water change. It is very stressful to the fish and to their owner.

A good starting schedule is to change 25% of the water bi-weekly.

The water which is going to replace the old one should be put in a wide-mouth container at least 24 hours before the change in order to let the chlorine¹ escape the water.

After that, it's easy: just siphon out some of the old water, and replace it with new one. Note that old aquarium water is an excellent fertilizer for your garden.

Cleaning algae

While doing a water change, it is a good time to clean the algae that have probably started growing on the glass.

In a normal aquarium algae will eventually appear on the glass. This is perfectly normal, and if the algae growth is not excessive, is a sign of prosperity. Most types of algae are harmless, and can be easily removed by scraping them off the glass.

Algae scrapers are sold in fish stores. Alternatively, you can use a razor blade or a toothbrush. Be careful not to scratch the glass.

---

¹ Chlorine is put in tap water to eliminate bacteria, and is very damaging to the fish. If you urgently need to put freshly drawn tap water into the aquarium, treat it with chlorine removing chemicals first. These should be available at fish stores.