Water Water Water

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My municipal water supply comes out of the mighty Yellowstone River originating many miles away in the high country of Yellowstone National Park. Tributaries originating in the Beartooth , Bighorn , Absaroka and Pryor Mountains also feed into it. 100 % of this water is snowmelt. Snow is rain in another form and is nearly distilled water. Recent late snow in the elevations over 7,000 feet and a lot of rain have worked together to cause flooding of Brobdingnagian ( how's that for a big word @Colin_T ) proportion on the aforementioned mighty Yellowstone River. Now to the point of this post. Changing water conditions. Today my water coming out of the tap reads 49 PPM TDS. I don't care who you are , that's soft water with low mineral content. Later this will increase until it gets to a reading of approximately 180 PPM TDS in winter and then the whole process begins anew next spring. What effect does this have on fish reproduction ? An inquiring mind wants to know.

 

[Wills]

My municipal water supply comes out of the mighty Yellowstone River originating many miles away in the high country of Yellowstone National Park. Tributaries originating in the Beartooth , Bighorn , Absaroka and Pryor Mountains also feed into it. 100 % of this water is snowmelt. Snow is rain in another form and is nearly distilled water. Recent late snow in the elevations over 7,000 feet and a lot of rain have worked together to cause flooding of Brobdingnagian ( how's that for a big word @Colin_T ) proportion on the aforementioned mighty Yellowstone River. Now to the point of this post. Changing water conditions. Today my water coming out of the tap reads 49 PPM TDS. I don't care who you are , that's soft water with low mineral content. Later this will increase until it gets to a reading of approximately 180 PPM TDS in winter and then the whole process begins anew next spring. What effect does this have on fish reproduction ? An inquiring mind wants to know.

There are definitely more qualified people for this here than me but very interested to see what people think.

From what I've read and seen on things like this I have a feeling a lot of the fish we keep live in this situation with hardness fluctuating through the year but at a point where your not going to get real extremes. Thinking of a lot of natural rivers and bodies of water that constantly have rain water and snow melt feeding them it has to happen like that. There will be exceptions and they are large haha! Eg the Rift Lakes in Africa and large stretches of the Amazon that are pretty slow moving.

But most of the fish we keep must experience fluctuations like in your water - just think of any aquatic life between you and the snow they are living naturally in the same situation.

Wills

 

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@Wills I am also wondering about a natural seasonal breeding cycle that ties in with this fluctuation. With our closed indoor aquariums and the expectation that fish should spawn whenever we like are we overlooking something that may be adding to a lack of success at breeding certain fish ?

 

[Byron]

I am here speaking only of very soft water fish, as my 30+ years has been with such fish. These fish do not experience any variation in pH, GH, and very little in temperature. They can usually be induced into spawning by doing a massive water change with slightly cooler water; some sources now recommend slightly warmer water--which to me suggests that it is the slight temperature variation either way. The pH and GH are not going to change simply because there is no mineral coming into contact with the water, be it rain or snow melt. This applies to most of the characins, Corydoras, and many of the rasboras.

Fish from hard or hardish water are a very different thing, and I will leave it to those aquarists experienced with these to comment.

 

[Wills]

I am here speaking only of very soft water fish, as my 30+ years has been with such fish. These fish do not experience any variation in pH, GH, and very little in temperature. They can usually be induced into spawning by doing a massive water change with slightly cooler water; some sources now recommend slightly warmer water--which to me suggests that it is the slight temperature variation either way. The pH and GH are not going to change simply because there is no mineral coming into contact with the water, be it rain or snow melt. This applies to most of the characins, Corydoras, and many of the rasboras.

Fish from hard or hardish water are a very different thing, and I will leave it to those aquarists experienced with these to comment.

Hi Byron - would that not happen in any water way though? If you look at a wide spread tetra like the X-Rays would they not come into contact with a range of parameters through their life? Even if it was ranging from 1 to say 8 Gh?

Then secondly in write ups from field reports you see hardness and ph fluctuating depending on location and also different trips at different times - some of this could just be better equipment over the years but could be some changes? The example I was going to reach for was a video from Gary Lang who was talking about collecting rainbow fish, on the first visit to the location Heiko Bleher had reported soft water and a low ph but 3 further times he had been to the same location it was hard and high as expected - but I realise this example is a hard water species but from memory I know I've seen the same discussion for fish from South America.

Wills

 

[Byron]

Hi Byron - would that not happen in any water way though? If you look at a wide spread tetra like the X-Rays would they not come into contact with a range of parameters through their life? Even if it was ranging from 1 to say 8 Gh?

Then secondly in write ups from field reports you see hardness and ph fluctuating depending on location and also different trips at different times - some of this could just be better equipment over the years but could be some changes? The example I was going to reach for was a video from Gary Lang who was talking about collecting rainbow fish, on the first visit to the location Heiko Bleher had reported soft water and a low ph but 3 further times he had been to the same location it was hard and high as expected - but I realise this example is a hard water species but from memory I know I've seen the same discussion for fish from South America.

Wills

The variance is not anywhere as great as some make out. I guess that was my point and I didn't phrase it well. And I was thinking mainly of the Amazon basin, should have been clearer on that too. But take the Rio Nego for example, the pH remains very acid and the GH is next to zero. There is no mineral for rain to come into contact with, and there is no mineral over which the rive passes--so it cannot possibly vary much above these numbers.

Something I forgot earlier--the fish in such areas spawn when the rains begin, not because of varying parameters but because the forest surrounding the rivers and creeks floods for more than 30 kms, and the fish move into this flooded area because of the plentiful insect life for food for fry.