Routine maintenance

A simple routine

Fish depend entirely on you. Most tasks are quick; what matters is doing them regularly, and writing down the test results to spot any drift.

Every day

Watch the fish at feeding time: swimming, appetite, breathing
Check the temperature
Make sure the filter and heater are working
Remove uneaten food

Every week

Change 10 to 25% of the water
Siphon debris from the substrate
Clean the glass
Test ammonia, nitrite and nitrate

Every month

Rinse the filter media in water removed from the tank
Trim the plants, remove damaged leaves
Check pH and hardness
Clean the filter pump’s impeller

Changing the water step by step

Prepare the new water
At the same temperature as the tank, with conditioner dosed for the volume added.
Switch off the heater and filter
A heater out of water can crack or overheat, and a pump must not run dry.
Siphon
With a self-priming siphon, never by mouth: tank water can contain bacteria that are dangerous to humans. Push the bell into the substrate to suck up the debris.
Rinse the filter media if needed
In a bucket of water removed from the tank, never under the tap.
Refill gently
Pour the water onto a saucer or against your hand so as not to stir up the substrate.
Switch back on and check
The filter must restart (prime it if it has taken in air) and the heater must come back on.

How much water to change

OATA advises up to 25% a week, Tropica about 30% once the tank has settled. The right amount depends on the stock, the feeding and the plants: let the nitrate level guide you, as it should stay low. Several small changes are better than one very large one, which upsets the water chemistry.

If you measure…	What to do
Ammonia or nitrite	Do not feed for one to three days, change 25 to 50% of the water and repeat on the following days until it is back to zero. Check the filter.
Nitrate rising from week to week	Change more water or more often, feed less, add fast-growing plants.
A falling pH	Measure the KH: an exhausted KH lets the pH crash. Regular water changes bring in fresh carbonates.
An abnormal temperature	Check the heater with a separate thermometer; in summer, fan the surface.

Corrective measures taken from the recommendations of the University of Florida and OATA.

Looking after the filter

Clean it when its flow drops, usually once a month, no more often than needed.
Squeeze the sponges in water removed from the tank: the aim is to remove the sludge, not to make them like new.
Do not clean the biological media at the same time as the others, and never replace them all at once.
Take out and rinse the pump’s impeller: debris wrapped around it reduces the flow.

Spotting warning signs

Every fish has its habits. A change is often the first sign of a water problem or a disease:

Behaviour

Stays at the surface or rests on the bottom
Erratic swimming
Hides more than usual
Unusual aggression

Breathing and appetite

Gill covers beating fast
Mouth open at the surface
Refuses food
Weight loss

Appearance

White spots on the body
Cottony threads
Damaged fins or missing scales
Dull or darkened colours

Going on holiday

A balanced tank can go two to three weeks without a water change: do one the day before you leave.
Ask someone you trust to drop by every day to check the tank and feed the fish, with portions prepared in advance.
An automatic feeder must be tried out before you leave and checked while you are away.
Avoid “holiday” food blocks: they release a lot of food at once, which rots in the water.
Underfeeding is better than overfeeding: fish cope far better with fasting than with polluted water.

Key points

Change 10 to 30% of the water every week, at the right temperature and treated with conditioner.
Rinse the filter in tank water, never under the tap, and never all the media at once.
Test the water every week and write down the results.
At the slightest unusual behaviour, test the water before treating.

Sources

Written by Aquarius from these sources. They do not replace a vet's advice.