Freshwater Aquarium Setups and Care

Freshwater aquariums are alluring and beautiful, but many people shy away from keeping a tank because it seems complicated. While a freshwater aquarium isn’t overly difficult to set up or maintain, it does require some research, attention and commitment.

Many novices want to bring their new tank home, fill it up and get their fish in as soon as possible. This is a big mistake, warns Bob Israel, a longtime freshwater aquarium hobbyist and board member of the Delaware County Aquarium Society in Pennsylvania. You will need to be patient: Israel recommends waiting three weeks before you add fish to your tank in order to give the tank time to accumulate the healthy bacteria that will keep your fish happy and thriving.

Keep the Tank Fish-friendly

According to Israel, tank maintenance is one of the biggest factors in an aquarium’s success. Some sources recommend replacing 25% of the water every two weeks, but Israel recommends a weekly water replacement of up to 50%. Siphon out a portion of the water and replace it with treated tap water that matches the temperature of the existing tank water.

Freshwater aquariums should range in temperature from 72–78 degrees, Israel says. While most freshwater fish should be comfortable in this range, some types of fish prefer water on the higher end of the range and some on the lower. Purchase a heater and a thermometer to maintain the right temperature for your fish community.

Be sure the new water is treated with a dechlorinating agent to remove chlorine, chloramine and trace metals typically found in municipal water. A water quality kit will help you regularly test the levels of ammonia, nitrite, pH and specific gravity. Follow kit instructions for acceptable levels and testing frequency.

A quality power filter is essential to your tank and must be cleaned regularly to keep it working well. But be careful not to clean the filter too often or too carefully. Leave some of the buildup in the filter; it’s full of good bacteria.

Provide Adequate Space and Light

Many experts recommend purchasing at least a 20-gallon tank for your fish. A larger tank allows for more water volume, so it takes longer for the water to become dirty. While opinions differ about the correct number of fish to keep according to the size of the tank, it’s good to err on the side of a larger tank with fewer fish. Talk to the expert in the aquatics department at your local retailer about the specific type of fish you plan to purchase and how much space they need.

Your freshwater fish and aquatic plants will benefit from a regular source of light. But, beware, too much light encourages algae growth in the tank, so it’s important to regularly scrape the algae from the tank’s sides and from decorative objects within the aquarium. To control light exposure, Israel suggests an aquarium light on a timer. That way, for example, the light can be on when you’re home enjoying your fish, but automatically switch off when you’re away or sleeping.

Finally, keep in mind that fish grow! Do some research to find out the typical adult size of the fish you plan to purchase and make sure you have enough room in your tank for all those full-grown fish.

Add New Fish Slowly

Instead of choosing a lot of different fish and adding them all at once, add fish in small batches of five at a time, Israel suggests.

Many experts recommend quarantining new fish for 30 days in a separate aquarium to ensure they are healthy before introducing them to your main tank. If keeping a quarantine tank isn’t possible, Israel recommends reducing the risk of obtaining unhealthy fish by buying from a reputable source and watching the fish for a bit before you buy them to make sure they are active and swimming around.

You can mix and match most freshwater fish that fall into the “community fish” category (meaning, they get along with other fish), but talk to an expert before you commit to a new variety; let him know what you already have in your tank to make sure you get the most compatible combination.

Keeping an aquarium thriving is not an exact science. There are many factors at work, so read as much as you can, talk with the experts where you buy your fish, join online forums like The Planted Tank and share your experiences with other fish fanatics. That’s part of the fun!

Maintaining a freshwater aquarium can be a highly enjoyable hobby. “I call it my indoor garden,” Israel says. “I can do it year-round, and it always keeps you thinking and watching.”