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Learn how to set up a saltwater fish tank and key considerations regarding placement, supplies needed, and the overall set up process.
Updated on October 23rd, 2025
Learn how to care for Marine FOWLR Aquariums. These tanks have easier upkeep and require less testing and supplementation than a reef tank. You can keep many fish who would generally consume corals and invertebrates, making it a popular setup choice for more aggressive fish.
Updated on October 23rd, 2025
Learn how to care for freshwater community fish, recommended diet & aquarium setup. Find the right food, supplies & equipment at your neighborhood Petco.
Updated on April 9th, 2026
Learn how to take care of Large Marine Angelfish, recommended diet and tank setup. Find the right food, supplies and equipment at your neighborhood Petco.
Updated on April 9th, 2026
Learn how to care for a marine snail, recommended diet and aquarium setup. Find marine snails for sale, supplies and equipment at your neighborhood Petco.
Updated on April 9th, 2026
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
Yes it is possible, however, unless you have a lot of experience keeping saltwater fish, please do not even attempt it. Most wild caught saltwater fish will not feed when they are in an aquarium, and only a small percentage will ever learn to feed. Please leave them where they are happy and healthy and where they belong, the sea.
Updated on September 24th, 2025
If it is on the glass, remove enough water to drop levels below the lotion and wipe with paper towels until clean. Avoid soaps or cleaners which can cause more harm to your fish than the lotion. Replace water with aged or conditioned water that is temperature matched to prevent further stress or shock. Use a fresh carbon filter insert to remove any residual lotion or chemicals. If the lotion is on tank furniture, remove and wash with a mild soap then rinse very well before returning it to the tank.
Updated on September 24th, 2025
Non-iodized salt can be used as an immersion bath (short term) at 10-30 g/L for up to 30 minutes. Keep a close eye on the fish for stress or rapid respiration as some fish can only tolerate the higher dose for minutes. This can be repeated every 2-3 days. It is difficult to determine in the pictures whether this is a parasitic problem or not. Black areas can be the result of melanin pigments, a sign of trauma. A visit to a veterinarian acquainted with fish could perform a skin scrape and examine under the microscope for a diagnosis. Good luck.
Updated on September 24th, 2025
The small size will limit the species of fish as well as the number. White Cloud Minnows or Guppies would do fine in a small tank. You could keep no more than 2 or 3 fish total. If you are looking for company for your Betta, the same species can be kept. Other options include Otocinclus (Otos), Corys, Platys or Harlequin Rasboras. Again, no more than one or two in addition to the Betta. Water changes for any tank are simple. Change no more than 30% total volume at a time. Use a water conditioner to remove harmful chemicals and make sure the water is temperature matched to prevent stress or shock. Rinse the filter in tank water, not tap water, to preserve beneficial bacteria. Vacuum the substrate every couple of weeks.
Updated on September 24th, 2025