Fish are at the top of tank but Water looks ok? Water hardness is not so great?

My guppies are at the top of my tank and will only swim a couple of inches down for only a few seconds. Why? I have attached my water results. Suggestions strongly welcomed!

We will need more data here. Tank size, how long set up, are the fish new (when added), all fish in the tank. If the fish have suddenly started this, how long? A video might help, if that is possible, as we can see just how the fish are behaving.

As for the test numbers, nitrite is fine (zero is where it should always be), nitrate at 10 is OK. The GH and pH are problems though. Guppies are livebearers and all livebearers must have moderately hard or harder water, and a basic (above 7) pH. The very soft and slightly acidic water here is detrimental to these fish and will weaken them which brings on other issues. I am not saying this is the issue, but it is a factor in any issue and depending upon how long you have had them it could actually be the issue.

I asked about other fish in the tank, as there are species well suited to this soft water that will not do well if you were to ask about making the water harder for the guppies, so we need to know everything.

Byron said:

We will need more data here. Tank size, how long set up, are the fish new (when added), all fish in the tank. If the fish have suddenly started this, how long? A video might help, if that is possible, as we can see just how the fish are behaving.

As for the test numbers, nitrite is fine (zero is where it should always be), nitrate at 10 is OK. The GH and pH are problems though. Guppies are livebearers and all livebearers must have moderately hard or harder water, and a basic (above 7) pH. The very soft and slightly acidic water here is detrimental to these fish and will weaken them which brings on other issues. I am not saying this is the issue, but it is a factor in any issue and depending upon how long you have had them it could actually be the issue.

I asked about other fish in the tank, as there are species well suited to this soft water that will not do well if you were to ask about making the water harder for the guppies, so we need to know everything.

Click to expand...

The tank is 75 litres. It has 5 guppies, 4 Cory and a tetra. The tank has been running since the 7th of January. I had an ammonia spike 2days ago. They were at the top two days ago and now they started again this morning. I have just added ph raiser now and they are going deeper but only for around a minute now. I will test the water again soon!

Please don't use a chemical to increase pH.

Cories and tetras are soft water fish; guppies are hard water fish. They are not compatible. If you add something to increase hardness, GH (not pH), the cories and tetra won't be happy. If you do nothing, the cories and tetra will be happy but the guppies won't.

It is much easier to keep fish that come from water with a similar hardness to your tap water.

laingdda said:

The tank is 75 litres. It has 5 guppies, 4 Cory and a tetra. The tank has been running since the 7th of January. I had an ammonia spike 2days ago. They were at the top two days ago and now they started again this morning. I have just added ph raiser now and they are going deeper but only for around a minute now. I will test the water again soon!

Click to expand...

First off, do not use pH adjusting chemicals/products with fish in the tank. This is detrimental to fish on a couple of fronts: first, substances in the water get into the fish's bloodstream continually and this weakens and stresses all fish, and second these products do not work long-term and the fluctuating pH is harder on the fish than leaving it alone.

The pH is tied to the GH and KH, and if one decides to raise the GH the pH will follow suit but it has to be done safely and naturally. I won't get into that now. But your soft water fish (cories and tetras) are better with the GH and pH you have now. Removing the guppies would be the easy fix because your source water is and will remain good for soft water fish.

This sounds like a water quality issue, likely ammonia from some source. What is the ammonia test number? If the source (tap) water has zero ammonia, a substantial water change will help. Use the conditioner, nothing else.

Raising the GH will not have a true effect on the pH. Raising the KH however, will. My water is truly terrible for most species. Directly from the tap on the API drop kits I measure a pH of 8.8 off the charts dark purple. HOWEVER I measure only ONE DROP on both the GH and KH tests. The lowest possible reading. In addition, I usually read .5 ppm of ammonia. If left alone, I have seen the pH fall to 6.2 within 24 hours. This type of swing will kill basically any fish. Despite many efforts, I have found it impossible to stabilize the pH without it remaining very high.

If I AGE the water before I use it... The pH may remain near the 6 mark, but with no KH, it may not. Either way, using only aged water is extremely inconvenient and not realistic for me. I've lost fish due to crashes more than once. I've gotten better with keeping my systems buffered but it's tough. Having crappy high pH but low KH treated city water sucks bad.

Today, my results look better, guppies are still near the top but not always at the surface.

I have 4 Cory, a tetra and 5 guppies in a 75 litre tank. It has been running since early January and has been cycled. The fish were all fine until a couple of days ago where my water hardness and ph started to reduce, following that my nitrite and nitrate went up. I have since taken my nitrite to 0 and nitrate is low. There is no ammonia. The guppies is swimming constantly at the water surface while my tetra is always no less than three inch from the top of the tank. My Cory seem to be acting normal. I have managed to raise my ph and water hardness in the last few hours. I have attached the results. My guppies are swimming low in my tank for a short while before they then quickly return to the top. What could still be wrong? Could it be stress? Will it take a while for the fish to recover from the last few days? What else can I do? Should I start to feed them again?

mjfromga said:

Raising the GH will not have a true effect on the pH. Raising the KH however, will. My water is truly terrible for most species. Directly from the tap on the API drop kits I measure a pH of 8.8 off the charts dark purple. HOWEVER I measure only ONE DROP on both the GH and KH tests. The lowest possible reading. In addition, I usually read .5 ppm of ammonia. If left alone, I have seen the pH fall to 6.2 within 24 hours. This type of swing will kill basically any fish. Despite many efforts, I have found it impossible to stabilize the pH without it remaining very high.

If I AGE the water before I use it... The pH may remain near the 6 mark, but with no KH, it may not. Either way, using only aged water is extremely inconvenient and not realistic for me. I've lost fish due to crashes more than once. I've gotten better with keeping my systems buffered but it's tough. Having crappy high pH but low KH treated city water sucks bad.

Click to expand...

This is not the correct approach. I will try to explain, as there is more than one factor here.

First, your near zero GH and KH will result in an acidic pH. This is natural and to be expected. If you only select soft water fish species you will have no problems, and you can let the pH lower as it likes. It will stabilize and the fish--provided they are soft water species--will be fine. I have had this situation for over two decades now. But I would never acquire fish that need moderately hard or harder water, as they cannot possibly survive in very soft water nor a pH below 7. But the GH is the more important for fish, so work with what you have.

Second, the tap water pH of 8...this is likely due to some substance the water authority is adding to raise pH. This is common in soft and very soft water regions. I have this here; our source water is 7 ppm GH, 0 KH, and a pH below 6. They add soda ash to raise the pH to 7 which lessens/avoids corrosion of water pipes and appliances. However, this is temporary. In an aquarium the pH will rapidly lower. I change 60-75% of the water in each tank once a week, and the pH rises maybe two or three decimal places but within a couple of hours is back to where it remains. This is not a problem for fish. Any attempt to change the pH with this situation (GH and KH) is risky and best avoided. If you have fish requiring harder water, the GH must be increased and the pH will follow suit because the KH will also raise with the GH. I've done this a couple times.

laingdda said:

I have 4 Cory, a tetra and 5 guppies in a 75 litre tank. It has been running since early January and has been cycled. The fish were all fine until a couple of days ago where my water hardness and ph started to reduce, following that my nitrite and nitrate went up. I have since taken my nitrite to 0 and nitrate is low. There is no ammonia. The guppies is swimming constantly at the water surface while my tetra is always no less than three inch from the top of the tank. My Cory seem to be acting normal. I have managed to raise my ph and water hardness in the last few hours. I have attached the results. My guppies are swimming low in my tank for a short while before they then quickly return to the top. What could still be wrong? Could it be stress? Will it take a while for the fish to recover from the last few days? What else can I do? Should I start to feed them again?

Click to expand...

First, to confirm, you have tested for ammonia and it is zero, correct? Ammonia does not show in the charts you have posted.

Second, how are you raising the GH and pH? This is crucial, as we have been trying to explain.

Byron said:

This is not the correct approach. I will try to explain, as there is more than one factor here.

First, your near zero GH and KH will result in an acidic pH. This is natural and to be expected. If you only select soft water fish species you will have no problems, and you can let the pH lower as it likes. It will stabilize and the fish--provided they are soft water species--will be fine. I have had this situation for over two decades now. But I would never acquire fish that need moderately hard or harder water, as they cannot possibly survive in very soft water nor a pH below 7. But the GH is the more important for fish, so work with what you have.

Second, the tap water pH of 8...this is likely due to some substance the water authority is adding to raise pH. This is common in soft and very soft water regions. I have this here; our source water is 7 ppm GH, 0 KH, and a pH below 6. They add soda ash to raise the pH to 7 which lessens/avoids corrosion of water pipes and appliances. However, this is temporary. In an aquarium the pH will rapidly lower. I change 60-75% of the water in each tank once a week, and the pH rises maybe two or three decimal places but within a couple of hours is back to where it remains. This is not a problem for fish. Any attempt to change the pH with this situation (GH and KH) is risky and best avoided. If you have fish requiring harder water, the GH must be increased and the pH will follow suit because the KH will also raise with the GH. I've done this a couple times.

Click to expand...

Nope. Don't agree here at all. I can add Seachem Equilibrium and it has an effect on the GH but minimal on KH. I still needed Sodium Bicarbonate to raise KH a decent amount. When I tried a planted tank, I had to use it because my water has no GH. Sodium Bicarbonate will raise KH but not really GH. I keep mainly goldfish. They truly aren't pressed about GH. It is low KH that causes pH swings that affect them. So long as I keep my water buffered, my goldfish do great. My pH stays very high so long as I keep KH high. Always a purple color.

Where does your theory of GH being more important for fish come from? That goes directly against what I learned. I learned that KH is much more important than GH. The GH in my tanks stays extremely low because I just don't have an affordable way of increasing it and I don't keep plants.

I tried Calcium Carbonate for a while a few years ago... But after making the error of mixing it and Sodium Bicarbonate together and it causing a horrible chemical reaction, I stopped using it.

KH impacts fish indirectly by stabilising pH.

GH is important as fish have evolved in water with a certain level of calcium and magnesium - that is, with a certain GH. Hard water fish excrete most of the calcium and magnesium they take in with the water, and in soft water they continue to excrete it. There is not enough calcium and magnesium in soft water to replace the excreted minerals so their bodies suffer calcium depletion. Soft water fish hang on to the calcium and magnesium in the water because there is not much in soft water. Put them in hard water and their bodies retain too much and they develop calcium deposits in their organs.
Both hard water fish and soft water fish do not live their expected lifespan if kept in the 'wrong' water.


I have just looked on Seachem's website for Equilibrium. The ingredients mention calcium and magnesium but not carbonate/bicarbonate. In other words, it will increase GH but not KH. This is why they say you also need a KH buffer with Equilibrium.

Yup. I agree with all posted there.

mjfromga said:

Nope. Don't agree here at all. I can add Seachem Equilibrium and it has an effect on the GH but minimal on KH. I still needed Sodium Bicarbonate to raise KH a decent amount. When I tried a planted tank, I had to use it because my water has no GH. Sodium Bicarbonate will raise KH but not really GH. I keep mainly goldfish. They truly aren't pressed about GH. It is low KH that causes pH swings that affect them. So long as I keep my water buffered, my goldfish do great. My pH stays very high so long as I keep KH high. Always a purple color.

Where does your theory of GH being more important for fish come from? That goes directly against what I learned. I learned that KH is much more important than GH. The GH in my tanks stays extremely low because I just don't have an affordable way of increasing it and I don't keep plants.

I tried Calcium Carbonate for a while a few years ago... But after making the error of mixing it and Sodium Bicarbonate together and it causing a horrible chemical reaction, I stopped using it.

Click to expand...

There are a couple different things to sort out here, so I'll do my best.

First is the Equilbrium. This is a plant additive; Seachem will tell you if you ask that it should not be used to raise GH for fish specifically, as fish requiring a higher GH also need a higher pH and KH. I used Equilibrium for I think four years, to raise the GH from zero to 4 or 5 dGH, solely to supply sufficient calcium and magnesium for the plants. The pH remained below or around 5 which was fine as I only had/have soft water fish. However, again this is plant-oriented, not fish.

Second on the sodium bicarbonate. This is not safe for fish, and it is not permanent. As organics increase they can reduce the buffering capacity so you end up adding more and more...and the fish are the losers. Every substance added to the tank water ends up in the fish's bloodstream and then internal organs. This alone is reason to use additives cautiously, but it also should mean we only use the absolutely essential additives to do the job as best with minimal side issues. The "horrible chemical reaction" you mention is evidence of why all these additives are risky if not downright deadly. An aquarium is governed totally by the laws of science, be they chemistry or biology. Interfering in any one aspect is never safe unless it factors in all of the resulting effects.

Back in the 1990's I was persuaded by well-intentioned aquarists to "buffer" the pH, and I did this for several years by adding two or three tablespoons of dolomite in a nylon bag in the filter chamber. It raised the pH from 5 up to 6.5 to 6.6 and it remained stable for the years I used it. I stopped back in the early 2000's because I saw no reason, given that I have wild-caught very soft water fish. This topic of buffering came up on Ian Fuller's CorydorasWorld FB page a couple weeks ago, and Ian told me that he uses RO water with no buffering, and his wild-caught Corydoras spawn and live with no difficulty, in spite of the zero GH and KH and a pH below 5.

Turning to the GH issue. Each species of freshwater fish has evolved over thousands of years to function in a very specific environment, which includes the water parameters. When the parameters are those for which the particular species' physiology is designed, it will function with the least amount of stress and difficulty. As soon as those parameters begin to shift away from the preferred or normal for that species, the fish has more trouble just carrying out the normal everyday life processes. This adds stress which further weakens the fish. The fish will succumb to issues like disease that it would otherwise and should be able to deal with, but being weakened it cannot.

GH is the most important parameter (perhaps equally with temperature, since both have such large impacts on a fish's physiology). The GH is the level of dissolved calcium and magnesium (primarily) in the water. Some fish species have evolved to require this, others do not. Fish requiring harder water (higher GH) will slowly weaken in softer water, and if they do not succumb to something along the way they will inevitably have a much shorter than normal expected lifespan. Similarly, soft water species kept in water that has a higher GH will assimilate the calcium from the water that continually enters via osmosis through every cell on their body. This water passes through the kidneys and the minerals are extracted--the fish has no control over this, it is how they function; as this continues, the kidneys become blocked and the fish dies. There are no external indications, but a necropsy will identify calcium deposits in the kidneys. A study in Germany in the 1980's determined that the higher the GH, the shorter the lifespan of cardinal tetras, and the cause of death was calcium blockage.

The pH will geenerally be tied to the GH and KH. If the water has a high GH, usually the KH is comparable and the pH will be basic (above 7). In soft water the GH is naturally low, and usually the KH and pH correspond. There are some exceptions of course, but we are dealing in general terms here. Amazon waters are very soft, and the pH is acidic. Waters in Central America have a higher GH and the pH is basic. The water in the rift lakes is similar, high in GH, KH and pH.

Very interesting indeed. Thanks for taking the time to write that. I keep highly modified fancy goldfish for the most part. Orandas mostly. They are really the only type of fish I am interested in and like. I really do not like "nano" fish and don't have the space or resources for "monster" fish.

Modern day fancy goldfish have fairly poor lifespans in general due to being so GMO and prone to literally everything.

I have had a tropical tank for nearly 2 years with a nearly 2 year old Blood Parrot and three nearly 2 year old Tiger Barbs and three nearly 1 year old Tiger Barbs and two nearly 1 year old Texas Cichlids. All fish gotten from PetSmart or Wal-Mart as tiny little fish.

Lifespans for some species is up in the air. There aren't concrete life expectancies for many species... And I truly do like GMO or "man-made" fish such as Blood Parrots and Orandas... So I never expected my fish to live 10-15 years anyway.

So long as they seem healthy and happy for a few years... I always thought that I was doing well. I mean most people with fsncy goldfish don't have them very long anyway, regardless of their water type. Goldfish are very tolerant of many water types... The fancies just die fairly easily anyway.