There is a particular joy in keeping a tropical fish tank. It takes work to maintain, but it’s so worth it. If you work hard to maintain your aquarium, it might be hard to imagine that things might go wrong. When they do, it often happens suddenly. The most likely cause of your aquarium fish dying off is poor water quality. 

Why Are My Fish Dying? 

You can’t afford to cut corners where tank health is concerned. Besides the pleasure and beauty an aquarium brings to your home, it’s also a significant investment. Plus, your fish are living creatures! They’re your pets, and you want to ensure they have the best quality of life. 

Of course, fish don’t live forever. There are many reasons why they might die off, including: Lack of oxygen in the water (yes! fish need oxygen too!) Water too cold or hot Bacterial infection Parasites Lack of beneficial bacteria, which might happen if the tank is brand new or if you do a complete water change (not recommended) Toxins in the water Overfeeding Starvation Not feeding the right food Wrong combinations of fish (causing aggression/predation) Stress Insufficient space/crowing If your fish are dying off and you don’t know why, you need to act quickly to eliminate all possible causes. Without a doubt, it’s a process of elimination. There might be no obvious or visible reasons. The first and most obvious thing you’ll need to address is water quality, and that’s what we’re going to talk about today. What Does Poor Water Quality Look Like? It is important to note that you can’t gauge your tank’s health simply by looking at it. Murky water might look off—and it could well be—but you won’t know unless you test—ditto for perfectly clear water. Keep in mind that you rarely see crystal clear water in nature. It might look pretty, but looks can be deceiving. If your fish are dying, you need to look deeper at the water composition for clues. Visually, you’d certainly know there was a problem if the water had ice on the top or if it was boiling hot. But you can’t see microbial issues, so regular testing is essential. Typical temperatures for a fish tank range between 74 and 81˚ F, depending on the type of fish you’re keeping. Some like it cooler, and some prefer it a little warmer. Temperature is, of course, the first thing you’ll want to look at. Other aspects of water quality include pH, water hardness, water oxygenation, nitrogen (nitrate), ammonia, phosphate, and carbonate. It might sound complicated, but with the right equipment and test kits, you’re golden. How to Test for Water Quality Testing your tank water is easy. You can purchase test kits and test strips from your local aquarium store or online. In best practice, buy a combo kit so you can test for everything. Many aquarium stores offer water testing too, so it doesn’t hurt to ask. Ultimately, doing your own testing is a much better option because you’re in total control. If you rely on the store to do your testing for you and we went into another lockdown, you might be in a pinch! Testing your water is easy with water testing kits. It’s generally a one or two-step process, and you’ll have results immediately. What to Test For The most important things to test for have to do with the fish’s waste cycle: nitrite, ammonia, and nitrate. Fish poop contains a lot of nitrates and will turn to ammonia in high concentrations—and too much ammonia is toxic to fish. You’ll also want to test the water’s pH. If the pH is low, it’s too acidic for fish to survive. If pH is too high, it’s alkaline. You want to aim for neutral pH, somewhere between 6.5 and 7.5. Marine environments tend to tolerate a higher pH than freshwater tanks, but it’s vital to get it right. Check these charts for detailed information on water parameters for home aquariums. Testing the above four elements is imperative, but if your fish are dying, you might want to go a bit deeper and test for ingredients found in tap water, such as chlorine, phosphate, chloramine, and copper, as well as GH (General Hardness) and KH (alkalinity, or Carbonate Hardness). If you have live plants in your aquarium, it’s more important to do the additional tests as you’ll want to ensure they are healthy too. PH chart guide New Aquarium Testing and Care New aquariums are a concern for water quality as the nitrate level can rise quickly and become toxic, which could lead to fish dying off. If the nitrate level in the tank rises above 0 mg/ml, you need to act immediately. Nitrites build up when ammonium ions are oxidized. This is the most common killer of aquarium fish. A healthy nitrogen cycle, where beneficial Nitrosomonas bacteria convert nitrite into harmless nitrate, can take up to three months to establish. In the meantime, if you follow responsible practices—not overfeeding the fish or overcrowding the tank—you’ll avoid this problem, known as new tank syndrome. You’ll also want to avoid complete water changes. When changing the water in your aquarium, only replace it 15-20% at a time. More than that, you’ll upset the nitrogen cycle. But changing the water is essential as waste builds up quickly and changes the tank’s balance. For smaller tanks, change up to 15% of the water every week. If you have a larger tank, change up to 20%. If you’re using tap water, dechlorinate it by boiling the water and allowing it to sit for three days before use. Reverse osmosis works also, but the above (boil and sit) method doesn’t require any chemicals or special equipment, just a little planning. When you’ve finished your weekly change, test pH levels to ensure they’re in range. Achieving a Balanced Ecosystem As with most things we do to support life, balance is the key. Test frequently and keep an eye on the numbers. If you have concerns at any stage, test for everything and track your results. Schedule your water changes for the same day each week. Establishing a routine is the best way to ensure it gets done. Introducing beneficial bacteria via water additives helps stabilize the tank ecosystem or establish the habitat in a new tank. Be sure to condition your tank water before adding these solutions to be sure no chlorine is present. If you want to do more to ensure healthier, longer-lasting aquarium fish, Microbe-Lift products can solve your water quality issues, restore a healthy balance to your tank, and keep your fish as happy and healthy as they can be. Microbe-Lift Special Blend Add Microbe-Lift Special Blend to improve water clarity and break down fish waste. Special Blend helps create a stable biological system in freshwater or saltwater fish tanks and is highly recommended when establishing new aquariums. It’s safe and easy to use, and there is virtually no possibility of overdosing your tank, even if you exceed the recommended application. Microbe-Lift Nite-Out II Nite-Out II is a microbial water additive containing specially formulated nitrifying cultures to initiate, stabilize, or maintain nitrification. It immediately eliminates ammonia in your aquarium, reducing toxicity and helping establish a healthy tank environment. If you’re in a panic because fish are dying and you suspect it’s because of poor water quality, we recommend combining Microbe-Lift Special Blend with Microbe-Lift Nite-Out II. Using both solutions together will cycle your aquarium quickly and may help you prevent further loss. Microbe-Lift KH Bio-Active Booster Phosphates build up in an aquarium when the tank is poorly maintained or the water is not changed regularly. If you have too much phosphate, algae will grow. Though algae is mostly unsightly and does not directly impact fish health, water high in algae changes both the oxygen levels and the pH balance in the water—both of which will harm your fish. Phosphates are part of a tank’s ecosystem, but you want to keep the levels low. Optimal phosphate levels are less than 0.2 mg/L. Weekly water changes, judicious dechlorinating, and proper tank maintenance and cleaning will help keep phosphate under control. Other things that can increase phosphate are feeding too much, leaving uneaten food in the tank, and not cleaning the debris from your filters. Carbon filter media can leach phosphate into the water, and some buffers (used to stabilize pH) contain phosphate. Look for products with the least amount of phosphate. If phosphate won’t stabilize, it likely means the KH (carbonate alkalinity) is off. Using Microbe-Lift KH Bio-Active Booster will bring your tank back into balance. Whether you’re a new aquarium owner or a lifelong enthusiast, we hope these tips helped to expand your knowledge of aquarium water quality. Keep on learning! And stock up on the suggested Microbe-Lift water additives for a healthier, more balanced aquarium.