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Are all nitrate bad for fishes ?
- Thread starter anewbie
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Ammonia, nitrite and nitrate are toxic to freshwater fish. The first two act very quickly compared to the latter, which I suppose is why we get bombarded with YouTubers claiming nitrate is harmless at very high levels. There are enough studies now that we can understand that fish are detrimentally affected by nitrate, and the severity depends upon the fish species, the level and the exposure time. The cichlid authorities are now warning that hole in the head is more commonly a high nitrate issue, and cichlids are especially sensitive to nitrate. No fish should be subjected to nitrate over 20 ppm (this is using our aquarium tests, not the commercial water chemistry bit just so there is no misunderstanding), but many fish, especially soft and very soft water species cannot manage this high a level for long.
Nitrate, in the words of Neale Monks, most likely slowly weakens the fish until it becomes susceptible to various problems it would, without nitrate harming it, be able to readily handle.
It will take someone else to explain if nitrate in plant fertilizers is the same, but so far as I understand it is. And this is rather paradoxical, because the vast majority of the aquatic plants we maintain in our tanks do not take up nitrate at all--unless nitrogen is the lacking nutrient. As the majority of aquatic plants take up ammonia/ammonium, and they are faster at doing this that the nitrifying bacteria, with fish being fed plus the decomposition or organics in the substrate theeree is not likely going to be a shortage of ammonia/ammonium. Other nutrients, particularly but not always just, carbon (CO2 for most plants bicarbonates in hard water for a few plants) is likely the first nutrient to become exhausted--which is what spawned the "siesta" approach, another detriment to fish more than plants. In order for plants to use nitrate, they must change it back into ammonium, and this requires considerable energy that the plant will only do if literally forced. Aquatic plants are thus different from terrestrial plants which do use nitrate, one reason why terrestrial plant additives are so dangerous. Unless it is a high-tech system, adding nitrate is a waste of time and detrimental to fish long=term.
Nitrate, in the words of Neale Monks, most likely slowly weakens the fish until it becomes susceptible to various problems it would, without nitrate harming it, be able to readily handle.
It will take someone else to explain if nitrate in plant fertilizers is the same, but so far as I understand it is. And this is rather paradoxical, because the vast majority of the aquatic plants we maintain in our tanks do not take up nitrate at all--unless nitrogen is the lacking nutrient. As the majority of aquatic plants take up ammonia/ammonium, and they are faster at doing this that the nitrifying bacteria, with fish being fed plus the decomposition or organics in the substrate theeree is not likely going to be a shortage of ammonia/ammonium. Other nutrients, particularly but not always just, carbon (CO2 for most plants bicarbonates in hard water for a few plants) is likely the first nutrient to become exhausted--which is what spawned the "siesta" approach, another detriment to fish more than plants. In order for plants to use nitrate, they must change it back into ammonium, and this requires considerable energy that the plant will only do if literally forced. Aquatic plants are thus different from terrestrial plants which do use nitrate, one reason why terrestrial plant additives are so dangerous. Unless it is a high-tech system, adding nitrate is a waste of time and detrimental to fish long=term.
OP
OP
Yea; it is the 2nd part that I'm concern about; as many of the plant fertilizers will raise nitrate significantly and yet from your post they would be just as happy with ammonium (which i presume is not so toxic to fishes). Part of the motivation for htis question is whether I need to start making my own fertilizer that is nitrate free when i setup the large tanks with geo. ...
In the majority of cases, there will be ample ammonia/ammonium for the plants if fish are present and being fed. There is no definitive evidence that ammonia itself is actively taken up by plants, and ammonia will kill fish, plants, bacteria. How it works is that ammonia diffuses freely across the cell membranes of all organisms while ammonium does not. No one has ever suggested dosing ammonia/ammonium. Sensitive plant species could well be harmed by NH4+ at just 1 mg/l.
NO3 is toxic to many animals including people but since people are big it takes a lot to make us sick. Doesn't mater if it iNa NO3, KNO3, or any of the many salt varieties that are possible in an aquarium.
Fish waist contains significant nitrogen and phosphate as well as other nutrients.Nautaly mciro nutrients don't stay soluble in water very long and the water treatment process es water utilities use typically removes Micro nutrients from the water. So some people only need the micro nutrients plus the fish waist to get good plantgrowth. But if you have a very highly stocked tank or a shrimp only and you might need to ad some nitrogen and phosphate to the tank to get any plant growth.
There is plenty of evidence that plants can consume ammonia and nitrate. Some farmers actually apply a water ammonia mixture to their fields to fertilize the crop. Plant preferentially will consume ammonia , urea, and any amino acids in the water first. Only when this sources of nitrogen are non will they start to consume NO3. The reason for this is that NO3 is harder for plants to use.
Fish waist contains significant nitrogen and phosphate as well as other nutrients.Nautaly mciro nutrients don't stay soluble in water very long and the water treatment process es water utilities use typically removes Micro nutrients from the water. So some people only need the micro nutrients plus the fish waist to get good plantgrowth. But if you have a very highly stocked tank or a shrimp only and you might need to ad some nitrogen and phosphate to the tank to get any plant growth.
There is plenty of evidence that plants can consume ammonia and nitrate. Some farmers actually apply a water ammonia mixture to their fields to fertilize the crop. Plant preferentially will consume ammonia , urea, and any amino acids in the water first. Only when this sources of nitrogen are non will they start to consume NO3. The reason for this is that NO3 is harder for plants to use.
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OP
This is useful information but it still leaves me wondering why so much aquarium plant fertilize have a large amount of nitrate mostly in the form of kno3. From but your and @Byron answers it sounds like that stuff is not needed and the focus should be on micros.
Is phosphate bad for the fishes at 3 or 4 ppm? I did experiment for a while with phosphate salt adding it during water changes (1/8 teaspoon per ~20 gallons); and it seemed to benefit the plants but i'm unsure if at that level it is harmful to fishes.
Not all plant additives are the same, and those with nitrate are best avoided. The 17 nutrients plants need have to be available, and depending upon the plant species needs, and the fish load, all of the nutrients may or may not be sufficient and thus require supplements. But the operative word here is supplement. The fish can be affected by adding many of these, and if the tank is primarily a fish habitat then the fish must come first and the plants must make do. I term this sort of tank low-tech, or natural, and it is what I have maintained over my 30 years in the hobby. There are some nutrients that will be plentiful if there are fish in the tank and they are being fed; nitrogen is one of these. The only time you might possibly run out of nitrogen is in a high-tech tank that has mega light and diffused CO2. But in anything less, I find it unimaginable to ever have a nitrogen deficiency. Carbon is likely to become exhausted first.
This is why I recommend so frequently the "comprehensive supplements." As the manufacturers will plainly tell you, they are not intended to provide sufficient levels of all 17 nutrients to feed heavily planted tanks. They are supplements to ensure the nutrients that can often be minimal are present, and they are comprehensive. The proportion of nutrients in an additive is important. Ther are some nutrients that if present in excess can cause plants to shut down the assimilation of other nutrients. That's another story, but there again the fish will also be impacted. I havee used for years one product that certainly delivers what I've needed, and I believe there are a couple of others that do the same.
Seachem's Flourish Comprehensive Supplement has very little (perhaps not any now) nitrate, they included ammonium though that is likely not needed with fish in the tank as there will be plenty of ammonia/ammonium from fish waste. Brightwell Aquatics FlorinMulti has a near-identical ingredient list. And in the UK there is TNC Lite. The latter states they do not include nitrogen or phosphorus because these will never be limited in a fish tank.
Oxygen, hydrogen, carbon are not in these supplements because again there is no need to be adding them, they are naturally present, and again we are talking low-tech or natural planted tanks with fish.
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OP
Do you know if phosphate is bad for fishes? I'm thinking i might order the chemicals from nilogc since they are cheap and mix my own the question is what to put into it that is safe for the fish - i do know first hand that adding phosphate did improve plant growth i just don't know if it is bad for the fishes.
I would never mix my own with fish in the tank, never. There are so many risks. Some nutrients (iron, copper, zinc, manganese) are heavy metals and are toxic to fish and plants. Some are present with water changes (the GH factors in). As for phosphate, there is more in fish food than the plants could ever need. Unpolluted natural waters may have between 0.003 and 0.002 mg/l of phosphate, and an aquarium is more likely to have 1 to 5 mg/l.
I cannot go into all the data, but when you do it becomes evident that there is a fine balance between nutrients. Natural waters can be somewhat forgiving because of the vastness, but the confines of any home aquarium can be a death knell. The products I mentioned previously have that balance worked out. To save a few pennies, I would not risk my fish.
I have come across these considerations. An excess of phosphorus can lead to reduced zinc uptake, and an excess of iron the same. Magnesium uptake has been shown to be reduced with an excess of potassium, and apparently this is applicable in reverse too. A boron and/or magnesium deficiency can result from an excess of calcium.
KH2PH4 is safer fish I target about 1ppm (1mg/L) K2SO4. For macros I have also used Ca(SO4), CaCl2, MgCL2, MgSO4, and NaCl, KNO3, K2SO, KH2PM4 and CO(NH2)2 (urea) At different levels and not seen any harm. The macro nutrients for plants are Nitrogen (N), Potassium (K)Calcium (Ca), Magnesium (Mg) Phosphorous (P), (Sulfur (S), Chlorine (Cl). All are used in aquarium commercial products The Ca Mg compounds are typically used in Gh boosters and work best when dosed dry. You can use this nutrient dosing calculator to calculate the dose needed to reach a ppm target.
Generally I like keeping nitrate ppm levels for N and K equal with 1ppm phosphate and then apply a GH booster with 3 parts Ca to 1 part Mg which also supply all the S and CL plants need. Tap water typically has all Cl needed. but I use RO water so I have to add CL A GH level of 1 degree is enough for plants but some fish need more. So the amount of GH depends on the fish you keep not the plants.
The questions of are fertilizer ingredients safe is contentious. It breaks down to all fertilizer ingredients are dangerous to those that say they are all safe. The issue breaks down to the problem that no one can measure all of the nutrients plants need dissolved in the water while everyone has a nitrate test kit. If you look at past forum posts there are people that have kept fish successfully with nitrate levels up to 20ppm, mainly because their tap water has nitrate or because they have too many fish in the tank. while there are others that normally have very low to zero nitrate but suddenly have aspike and they loose fish
While it is known that animals can get sick from high nitrate level there is little lab verified dated for all the fish people keep. All agree that nitrates can harm fish. But few have any good data to what is a safe level. And different species of fish probably have different levels of tolerance Also NO3 levels are affected by the health of the plants and the other nutrients in the water.
For me early into this hobby I had zero nitrate and no plants were not growing. I couldn't figure it out. So on a whim I purchased a phosphate test kit. and found that the test kit was maxed out at over 30ppm. And it it was hard to keep it down. Eventually I tried adding some sachem nitrogen. Phosphate levels started to drop and my plants started to recover. But during recovery my KH changed rapidly but I didn't loose any fish. Eventually I learned that if I kept measurable nitrate and phosphate (about 1 to 5ppm) in my tank my plants did better and my phosphates . stayed low. But if either went to zero the plants didn't grow.
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OP
The problem with this statement is what is 'successful' fish keeping. If you keep a fish 5 years from birth to death is that successful? What if the fish normal life span is 4 years; what if the lifespan is normally 20 years. A good example are cory - many say that in good condition many species of cory can live 20+ years but most fish keeper don't have them anywhere close to that number of years. Then the question becomes why - was it poor genetic or poor conditions for the fish and if poor condition what was the poor condition; too much nitrate; too much calcium; too much this or too much that ? How do we really know if we are keeping our fishes 'successfully' ?
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Exactly.
plebian
Fish Fanatic
How do you explain the information in the attached documents then?
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