The water fish swim in is very important. But it is not nearly as important as people give it credit for. The chemistry of the water, the pH, the hardness, and the salts contained in the water, are just not very important to the well-being of the freshwater tropical fish.
If you can drink the water, fish can thrive in it
So don’t buy a test kit with your new aquarium. Just add a dechlorinator if you have tap water with chlorine in it and GO . Add fish when you are ready. And just don’t worry about the water. The “water parameters” are just not that important.
Notice EVERY time I say this on social media, the number of fish cops coming out of the woodwork to say, ” That’s not true, you idiot ” is amazing. But it’s just true!!! Add conditioner if the water contains chlorine and you’re good to go. The following points are relevant:
- The water in the aquarium should be as bacteria-free as possible. This requirement is important but rarely even mentioned or discussed. The number of bacteria correlates with the clarity of the water. “Crystal clear” water contains very few bacteria, while “cloudy” water contains very many bacteria.
- Close control and stability of temperature in NOT important. Temperature for almost ALL tropical fish can range from 70 to 90 degrees F. (21 to 32.3 degrees Celsius), with the occasional excursion to 65 degrees F (18.3 C.) to 95 F (35 C.). And fish are not “shocked” by rapid changes in temperature.
- The pH of the water is not that important. Most tap water between a pH of 6.5 and 8.5 is good for all fish. Some fish need a pH close to their birth water to breed.
- Hardness (both GH and KH) is of little importance, except that some hardness prevents the occurrence of “crash” or old tank syndrome. “Old tank syndrome” may not occur if one changes 50% water every one to four months (depending on the occupancy).
- Salts are not important as long as most fish have some. If you use Osmosis water, it becomes a little more important. The only time fish can get into trouble is if a fish is placed in very salt-free (total dissolved solids or TDS less than 60) water.
- The idea that water has “heavy metals” or “toxins” in it is a huge myth, propagated by those who sell products “designed to remove the heavy metals and toxins”. Isn’t the profit motive great? .
Water Changes
There is a myth that one should change the water in an aquarium at least once a week. This idea is patently false. Depending on occupancy, we recommend 50% every two to four months. These “water changes” ONLY remove nitrate from the aquarium. Water changes do NOTHING else in the aquarium.
Note that many very experienced hobbyists do not do water changes and do just fine. There is an entire fish store in San Francisco that has not done a single water change in ten years with probably fifty or sixty aquariums.
The only reason to change water is to keep nitrates low. And nitrates are just not very toxic. If one changes the water according to the nitrate level, I recommend changing the water only when the nitrate exceeds 80 ppm. Note that nitrates are ONLY reduced by water changes or plants. Here’s an article about it:
5.4. Safe Nitrate Levels
Myths About Water
There are many myths about the water in which aquarium fish live. Some of these myths are:
- It is essential one has a water test kit and that one tests the water frequently
- At least 50% water changes should be done once a week.
- It’s dangerous to the fish to “chase” pH with chemicals.
- High pH (>>7.5 pH) is dropped by using organic materials such as almond leaves, beech leaves, oak leaves, peat, and/or driftwood.
- The “water parameters” shown by water test kits are important when diagnosing fish diseases.
- Fish will have their lives shortened if put in a pH different than their native waters.
- Fish from the Blackwater Amazon will suffer in water with a high pH.
- The hardness (GH and KH) of the water is very important to the fish.
- Fish will have their lives shortened if put in a water hardness different than their native waters.
- Rapid changes (in seconds) in water parameters (pH, hardness, and/or temperature) can damage or kill freshwater fish.
- Temperatures need to be closely held for healthy fish and heaters are an absolute necessity in most homes.
- Stability in aquarium parameters (temperature, pH, hardness) over hours or days is important.
- Nitrates going above 10, 20, 40 or even 80 ppm will shorten the life of an adult fish.
- Ammonia levels at some level below 5 ppm or nitrite levels below 1 ppm are detrimental in any way to fish at a pH of 7.
- Ammonia levels at 5 to 10 ppm or nitrite levels from 1 pm to 5 pm are very toxic to fish at a pH of 7.
- When shipped fish are un-bagged, they should be gradually acclimated to their new water chemistry.
- Water that has been run through a water softener is bad for fish
- Water changes remove built-up toxins and fish hormones in the water.
- Water changes are bad because they cause variation in the water parameters.
- Primetm and Safetm are superior water conditioners that also “neutralize” ammonia, nitrite, nitrate, and heavy metals.
- There are products that “neutralize” ammonia and nitrite (Tetra AquaSafe Plus, Kordon AmQuel, ClorAm-X, Hikari Aquarium Solutions Ultimate, SeaChem AmGuard, API Ammo-Lock, API Stress Coat).
- It is beneficial to add “bacteria in a bottle” such as Stability for every water change.
All these myths are simply false
To go into the subject of Water Parameters in more depth click on the following link:
4. Temperature, pH, KH and GH
Startpage Aquariumscience
Source: Aquariumscience.org – David Bogert
Startpage Aquariumscience
Source: Aquariumscience.org – David Bogert
The author, David Bogert, is a certified chemist, something that is only useful in the sections on chemicals such as conditioners and fertilizers. He has about 43 patents, mostly in the medical device field, which only helps with some DIY designs. But he also spent much of his life as a scientific researcher working on literature research, data analysis, statistics, and a little-understood field called “experimental design.” This experience is very applicable to ALL fishkeeping science. The author has been keeping all kinds of aquariums and all kinds of fish for over 54 years. He currently has ten large and many small aquariums. But note that he is not an “expert” in all aspects of aquarium keeping. The ecology of an aquarium is far too complex for anyone to be a true “expert” in all the different aspects. One can only search the journals and books for relevant research in each individual subject.
