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Tanks with live plants can be excellent additions to your home, bringing a touch of nature indoors. Learn how to take care of aquatic plants.
Updated on November 6th, 2025
Discover the fish tank filter system that’s right for your aquarium. Learn about mechanical, chemical, and biological filtration at Petco.
Updated on June 19th, 2026
Learn how to care for a Koi, recommended diet and aquarium setup. Find Koi for sale, supplies and equipment at your neighborhood Petco.
Updated on April 9th, 2026

There's a wide array of heating solutions to provide the optimal temperature for your aquatic friends to thrive. Dive in to navigate options & ideal wattage.
Updated on July 17th, 2026
Learn how to care for large marine fish, recommended diet and habitat setup. Find the right food, supplies and equipment at your neighborhood Petco.
Updated on April 9th, 2026
Hello, and thank you for using PetCoach. The most common (and easiest) way to clean a fish tank is with a siphon-style cleaner. Fish tanks should be cleaned in stages, generally replacing 10-15% of the water at a time. There are times where a larger cleaning might be necessary, but removing the fish and changing too much of the water at once can be quite a shock and can be dangerous to the fish, so this should be saved for only extenuating circumstances. Here's a helpful video on using a siphon cleaner: http://video.petco.com/v/18852/how-to-clean-your-aquarium-with-the-aqueon-siphon-vacuum-/ And some more reading you may find interesting on general fish tank cleaning and maintenance: http://www.firsttankguide.net/waterchange.php Hope this helps!
Updated on September 24th, 2025
Anything less than a 100 gallon tank would be insufficient for koi of your sizes. They can be fed as you feed outdoors. Filtration would be critical to maintain water quality. A combination of mechanical, biological and chemicals filtration would be required.
Updated on September 24th, 2025
I'm sorry you are having difficulties with your aquarium. There are several issues that should be dealt with right now. They are water chemistry, aquarium size and choice/number of fish. Any new aquarium should be set up and, ideally, run empty for several weeks (usually 4-6 weeks). This is so beneficial bacteria have an opportunity to populate the substrate and filter. These bacteria are necessary to break down wastes that fish will produce. The technical phrase for this is "establishing the Nitrogen cycle". These bacteria will break down wastes into ammonia then nitrites then nitrates. Nitrates can then dissipate or be absorbed/used by live plants. In high enough concentrations, ammonia and nitrites are toxic and can kill fish. Cycling a tank with fish is possible but it increases the risk of loss. Water chemistry should be checked every few days using a liquid home test kit. A water sample can be submitted for testing , but is not as convenient as testing yourself. Most pet stores or fish stores will do this for free or for a small fee. Partial water changes, no more than 30%, can be done as needed to stabilize chemistry and maintain water quality. Choices for water conditioners include NovAqua, AmQuel Plus, Prime, StressZyme or StressCoat. Tank size is another concern. With most fish, the widely accepted "one inch of fish per gallon" will be sufficient. For koi and other carp species, including goldfish, the rule is not sufficient. At full size, goldfish need 20 gallons per fish with an additional 10 gallons for each additional fish. Koi do best in larger tanks, much larger...we're talking in the hundreds of gallons or small ponds. These species produce a larger than average bio-load (wastes) that can quickly affect water quality in a tank. To combat this, large water volumes and powerful filtration are required. Any filter should be rated for at least twice the tank volume. I'm not sure what size tank you have now, it may be fine if the fish are young and small, but they will quickly outgrow it. The last issue is choice of fish. Koi and goldfish are cold water fish. They do best in water between 65F and 72F. Most species of sharks do best in the high 70sF to low 80sF. Keeping fish in incorrect water temperatures will lead to stress and illness. This could be compounded by the water quality/chemistry issues you are having currently. Until the chemistry is stable and water quality is maintained, your fish will continue to become ill and possibly die. Any treatment will not be successful in this situation. Do not purchase or add any more fish until the tank has cycled. If you have additional questions, you can post them in the forum or request a consultation to discuss the case in greater depth.
Updated on September 24th, 2025
Begin by submitting a water sample for quality testing. Most pet stores will do this for free or a nominal fee. High ammonia levels, PH imbalances may be responsible for that. Oxygen concentration and quality of the filters should be determined as well. Lack of oxygenation could be the cause of it. If water quality is good and there are no major imbalances, Bubbles should examined to look for any sign of bacterial/fungal infection and eventually water should be treated. Please do not hesitate to contact us again on the forum or by requesting a consultation (where you can post pictures ) if you have any more questions or to discuss it any further.
Updated on September 24th, 2025
Thanks for reaching out. If is a good idea to fast for 1-2 days prior to shipment, this decreased feces and will help to keep the ammonia down. Typically clear bags are utilized with about 50% water, and 50% air/oxygen used. A local pet store might be able to assist, as they get shipment in (so have older bags and boxes, which need to be disinfected) and hopefully the skills to ship. Check with the airline also, box needs to be well labelled "LIE ANIMALS" and "THIS END UP". Sometimes a health certificate for interstate travel is needed, so contact airline and State of Utah, veterinarian. Good luck.
Updated on September 24th, 2025