Perhaps a successful fish keeper is one who pampers their filter bacteria?
Many problems which occur in aquariums, not just goldfish tanks, are due to poor water quality, which is why we have pinned a “must read before posting” topic on the disease and illness thread. Not all fishy problems are down to poor water quality, but it is the first and easiest thing to exclude.
Initially, you may have some tiny fish that you just bought, in an uncycled tank, where water quality is likely to kill them before you realize that the pet shop misinformed you. Assuming that you have read the articles about basic goldfish keeping and how to prepare your tank (cycle) for your new pets, what is “water quality”?
Water is water, no? No – it isn’t that simple, unfortunately! There are several very important water parameters which will keep your fish (and good bacteria) happy and healthy.
Firstly we would recommend that you purchase an API Freshwater Master test kit. They can seem a little expensive at the outset, but you will be able to test the water over one hundred times before needing to replace a bottle, which you can do individually, or in pairs. So many people post that they had their water checked by the local fish shop (LFS from now on) or the pet shop, and they were told that their water was “OK”. Does OK mean good, alright or borderline poor? Many issues could be avoided if you knew what OK is more precisely. That’s why you are better off with your own test kit.
So what do we need to test?
Ammonia: Ammonia is produced by rotting fish excrement and uneaten food but is also expelled by your fish through their gills.
- Ammonia is the most deadly toxin occurring in an aquarium. It exists as a dissolved gas in the tank (NH3, Ammonia), but also as a dissolved salt (NH4+, Ammonium), the gas form being much more toxic than the salt form. Unfortunately, the equilibrium between the two forms will depend on the pH and temperature of the water in your tank. NH3 Free Ammonia increases with higher pH and temperatures.
- It binds with the hemoglobin in the fish’s blood causing difficulty with gas exchange or “breathing”, as well as physically burning skin and gills
- In a cycled tank, this should stay at 0 ppm (parts per million). But don’t panic if it is 0.25 ppm, this is not the end of the world, it may just be a spike in your cycle. Just make sure it goes back down to 0 very soon. If it goes anywhere over 0.25ppm or stays at 0.25 ppm for a prolonged period, do a water change. During a fish-in cycle, it can be allowed to reach up to 0.5 ppm as long as fish are monitored. If you have a low pH, you can tolerate a higher level of ammonia easier (0.5ppm or even 1pmm for a very short duration).
- How to protect your fish: If you happen to have a spike of ammonia, what should you do? Start your water change immediately. Using a detoxifying agent like Seachem Prime or Amquel+ is also gonna help render the ammonia less toxic and prevent further damage. Adding aquarium salt at a concentration of 0.1% will also offer a mild ammonia protection. In emergencies with acute ammonia poisoning, methylene blue may be used to return hemoglobin to its normal function and allow the fish to get more oxygen.
- How to prevent ammonia buildup: Makes sure your aquarium is cycled and your filter is functioning properly. Make sure your filtration is enough to handle your bioload. Make sure you don’t have an accumulation of organic matter such as uneaten food or dead fish.
Nitrites: Nitrites (NO2–) are converted from ammonia by the first good bacteria which will arrive to colonize your filter – this can take many weeks, but they will come.
- Nitrites are less toxic than Ammonia, but they are still dangerous to your fish. It also affects oxygen levels in the blood, the same way as ammonia. Nitrite is more dangerous at low pH levels.
- Again, in a cycled tank, it should stay at 0 ppm. If you have any amount of nitrite in the water, do a water change. You can tolerate a higher level of nitrite if your pH is high (0.25 ppm for a very short duration).
- How to protect your fish: If you happen to have a spike of nitrite, what should you do? Start your water change immediately. Again, using a detoxifying agent like Seachem Prime or Amquel+ is also gonna help render the nitrite less toxic and prevent further damage. Adding aquarium salt at a concentration of 0.1% to 0.3% will also offer a mild to good nitrite protection. In emergencies with acute nitrite poisoning, methylene blue may be used to return hemoglobin to its normal function and allow the fish to get more oxygen.
- How to prevent nitrite buildup: As for the ammonia, makes sure your aquarium is cycled and your filter is functioning properly. Make sure your filtration is enough to handle your bioload. Make sure you don’t have an accumulation of organic matter such as uneaten food or dead fish.
Nitrates: Nitrates (NO3–) are the final step in the aquarium cycle – this is what the Nitrite eating bugs release back into the water.
- Nitrates are the least toxic of the “big three”. It is safe up to 20 ppm for goldfish. You should do a water change if it goes over that, but you don’t need to panic as the fish will tolerate higher nitrate for shorter periods of times without too many problems.
- Routine, weekly water changes are enough for most keepers to keep nitrates well under control.
- How to protect your fish: There is no real protection for nitrate as the fish can tolerate it fairly well for short periods. Again, Seachem Prime detoxifies nitrate, so you may add some to help protect your fish. The best way to reduce them is still with a water change.
- How to prevent nitrate buildup: As for the other two components, makes sure your aquarium is cycled and your filter is functioning properly. Make sure your filtration is enough to handle your bioload. Make sure you don’t have an accumulation of organic matter such as uneaten food or dead fish. Adding live plants to the tank will help greatly as the plants consume nitrates.
- The API Freshwater test kit also measures pH and comes with two separate bottles – a low range and a high range. At approximately 7.2 to 7.8 there is a crossover – at pH 6 and pH 8, you may only need to do one test but at the crossover, you will likely need to do both to see which one gives you the most accurate color match.
- Goldfish prefer slightly basic water – pH greater than 7 – but can tolerate a somewhat wide range of pH between 6 to 9, with the most important thing being stability. The ideal pH would be somewhere between 7.2 to 7.8.
- Note that sudden changes in pH are very harmful to your fish – it is better to leave them at a stable but slightly “off” pH than pouring bottles of “pH Up” or” pH Down” into it! As pH is a logarithmic scale, a pH of 7.0 dropping to 6.0 doesn’t look too much on your API test card, but it is ten times more acidic to your little fish. Therefore, remember to always match your pH when doing a water change.
- How to prevent pH swings: The best way you have to prevent swings is to have a good KH level. By buffering your KH, you will stabilize your pH, which is the more important thing.
- API also sell a KH/GH “Water Hardness” test kit, which tests for KH (Carbonate Hardness) and GH (General Hardness) of your water. What!!!!???
- KH is a measure of the dissolved carbonate (CO32- ) and Bicarbonate (HCO3– ) minerals in your water (it is sort of like Hard Water vs Soft water – does your kettle element get “furred up”?). KH is also termed “Total Alkalinity”.
- KH represents the amount of pH buffering your water will be able to manage – a buffer is something which opposes a shift in pH. As your good buddies in the filter munch bad toxins, they produce acid, which is absorbed by the KH, so the pH remains stable. But the KH will become depleted in the tank as the bugs munch and make acid. If your tap water KH is good, and you do regular water changes, you should not have a problem with this, but if you were to report a decreasing pH in your tank, you will now know why someone might ask you about KH.
- For goldfish, you want a KH of at least 100ppm (6 drops on your API test kit).
- GH and KH are independent – one can be high and the other low, but limestone rich areas will likely have dissolved Calcium Carbonate in the water, which will increase both.
- GH is not so important in a Goldfish tank, but it represents the amount of dissolved mineral in your tank, strictly the amount of divalent metal ions such as Magnesium (Mg2+) and Calcium (Ca2+). It is important if you kept shelled invertebrates for example – they need those minerals to make their shells!
Why have I constantly mentioned the API Freshwater Master Test kit?
The API kit uses a Salicylate based ammonia test – any test which shows results in shades of green will be salicylate based and should be as good. It will convert all of the Ammonia/Ammonium in the tank to Ammonia, and then give you a reading of the Total. Hagen (Nutrafin) manufacture various types of Ammonia tests – some are single bottle (Nessler) tests, others are Salicylate. Salicylate-based ammonia tests are more accurate and reproducible than Nessler tests, which is why we recommend them.
Test strips are unfortunately an entirely different story. Strips claim to be able to measure things that API cannot (such as chlorine), but as chlorine will be painful (at least) to your fish and lethal to your filter bacteria, there should never ever be any – you did use a dechlorinator didn’t you? So why measure it?
Plus, test strips are unfortunately wildly inaccurate, often seriously underestimating the amount of the bad “Big Three” in the tank. Liquid test kits are the best, they may be a little more expensive but they should last a good time.