How to Take Care of a 20-Gallon Fish Tank

A 20-gallon fish tank is a good size for many tropical fish. It is large enough to allow for many different types of fish, but small enough to simplify maintenance. The average 20-gallon tank is two feet long, which makes it a good size for even the smallest house or apartment. There are some basic routines that you can use in order to keep your aquarium attractive and your fish healthy. For the most part, these steps revolve around keeping the water clean---or avoiding getting it too dirty in the first place.

Things You'll Need

• Heater
• Aquarium thermometer
• Replacement filter media
• Gravel vac or siphon
• Algae scraper

Instructions

1. 

   Monitor your "fish load," or the number of fish in your tank compared to its volume. A rule of thumb is that you should not have more than one inch of fish per gallon of water.

2. Feed your fish every day to every other day. Be careful to not feed them too much, as excess food can rot at the bottom of the tank.

3. Test your water regularly, especially during the initial cycle and while adding fish. A standard test kit that measures pH, ammonia, nitrites and nitrates will give you insight into the chemical processes which occur in your aquarium.

4. Remove dead leaves from live plants and add aquatic fertilizer per the packaging directions (do not use a fertilizer not designed specifically for aquarium use). Plastic plants can be cleaned by removing them and running them under the faucet.

5. Do a water change of 10 to 15 percent every one to two weeks. This is also a good time to do other basic maintenance chores, such as cleaning algae off the inside of the glass.

6. Check your filter to make sure it is running correctly. Rinse and replace your filter media on the schedule recommended by the manufacturer.

Tips & Warnings

• Remember that fish grow. Base your calculations of how many fish will fit into a tank on their adult sizes. Live plants may seem like more work than plastic plants, but they clean the water and extract nutrients from the water, which might otherwise promote algae growth. Set your aquarium heater between 76 and 80 degrees F (check the specific preference for your fish species). Install a simple thermometer and check it regularly to make sure the heater is not malfunctioning--or unplugged.

• Remove dead fish promptly. They are not just a sad sight, but a health hazard to the other fish. Unplug your heater during water changes. Aquarium heaters are not designed to be run dry, and can be severely damaged if they come on during the water change.

References

• Aquarium Maintenance Schedule