pH + TDS = Effect on fish eggs?

kribensis12

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I'm very interested in the effect that tank pH and the TDS of the tank on fish eggs.

I have seen/heard many statements such as:

"The TDS, if too high, will cause eggs to calcify and prevent penetration by sperm"

"The pH, if too high (not like 9.5, but higher than the fish is naturally found in), will prevent fertilization"

"The TDS, if too high, will "clog" up the eggs walls and prevent the free flow of oxygen from the tank to the embryo, causing the embryo to suffocate"

Can anyone add to this conversation, or even better, point me in the direction of where I can find studies pertaining to this?
 

Colin_T

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TDS isn't a good measure of anything because it includes everything in the water ranging from minerals, silt, algae and anything else.

The pH and GH have no effect on fish eggs being fertilised because the eggs are only able to be fertilised within about 1 minute of being laid. Any calcium in the water is not going to be able to affect eggs within that time. After about 1 minute, the egg toughens up and stops sperm being able to penetrate the eggs.

The pH does affect what sex the fish produce. A pH above 7.0 will produce more male offspring, whereas a pH below 7.0 will produce more female offspring. This is more noticeable in species that come from acid water and are bred in water with a pH above 7.0, but it affects all freshwater fish.
 
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kribensis12

kribensis12

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TDS isn't a good measure of anything because it includes everything in the water ranging from minerals, silt, algae and anything else.

The pH and GH have no effect on fish eggs being fertilised because the eggs are only able to be fertilised within about 1 minute of being laid. Any calcium in the water is not going to be able to affect eggs within that time. After about 1 minute, the egg toughens up and stops sperm being able to penetrate the eggs.

The pH does affect what sex the fish produce. A pH above 7.0 will produce more male offspring, whereas a pH below 7.0 will produce more female offspring. This is more noticeable in species that come from acid water and are bred in water with a pH above 7.0, but it affects all freshwater fish.
Hey @Colin_T are you able to point me in the direction of where you have learned this information?

There is a pretty well respected Ram Cichlid breeder whom swears that his cultivar of the "Dark Knight" Ram will have unsuccessful spawns if the TDS exceeds 110. He does water changes every two days to prevent the TDS from exceeding that level.
 

Colin_T

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Saying he has a TDS of 110 doesn't mean anything without the rest of the water test results. What is the ammonia, nitrite, nitrate, pH, GH, KH, iron, copper, etc, levels? How much algae is in the water. How clean is the substrate and filter? What else is in the water? If they are in the UK the water has some pretty horrible stuff in, and the same applies to people living in rural areas who have well water.

If he has hard water his fish won't breed as well. If the pH is too high it could prevent the fish from wanting to breed. Malnourished adults won't breed as readily. Inbred fish won't produce as many healthy offspring and fewer eggs will be fertilised. There's a whole bunch of things that could b causing the problem.

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The pH, GH bit is from my own experiences and a few other people who did the same experiments as me confirmed the pH can affect the sex of fish fry.

A couple of scientists in ANGFA did experiments on fish eggs to see how long they would accept sperm for. There was also an article in a fish magazine years ago about the subject.
 
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kribensis12

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Thanks for your thoughts on this.

I know that the breeder does water changes every two days, has no substrate and a very clean looking sponge filter. That's all I know.

I'm getting a pair of Dark Knight Rams next week --> they are pretty rare and I want to make sure that I'm doing everything within my power to cater to them.

Does anyone else have thoughts/experience/data in regards to both pH and TDS and fish breeding? Or other thoughts on hardness etc.
 

Colin_T

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Find out what the pH and GH is at the breeders and start off with that. If it is high then slowly reduce it over a month or so.

If you ever have concerns about breeding a particular fish, just try to replicate its natural environment. Microgeophagus ramirezi come from soft acid water so start with that. Have the GH below 100ppm and the pH around 7.0 or slightly less.
 
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kribensis12

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Breeders pH is 7.2 - straight from the tap.

My pH is 8.4, so I've begun to mix in R/O + tap mix into their soon to be home to match those parameters + I am going to begin to add blackwater extract as well. Just wasn't sure if there is more I should be doing.
 

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Some time back while researching for an article on TDS, I came across this information which may be of interest. Source is:
Jensen, Niels (2009), “The Importance of Total Dissolved Solids in the Freshwater Aquarium,” as reposted on PlecoPlanet at http://www.plecoplanet.com/forum/showthread.php?t=3480

TDS and Low ph fish
As I stated earlier, when we talk of softwater fish or low pH fish, what we really are saying is that they are low TDS fish. Even though many of these low TDS fish have adapted to harder, higher pH water, (and often relatively higher TDS levels), there is one fundamental problem, especially for South American dwarfs : the eggs cannot adapt well in calclium and magnesium rich water, and cannot hatch. My own experiences tell me that high TDS levels (in my case, mainly due to high levels of calcium and magnesium ions) are the culprits. This is where I used to make mistakes. I would use different methods for lowering pH and hardness but would take no consideration of TDS values. Peat can solve this problem.
I now use peat to successfully lower calcium and magnesium levels and thus pH (as well as KH and GH), as well as TDS. Many of the dwarfs I tried this with seemed to be much more content and this was reiterated by their ensuing fry (cacautoides, apistos, ramirezis, and other S.A. dwarfs.
If you match your own water with the fish's natural water chemistry, keep TDS levels low. My own experiences have taught me that the mineral content of the water, specifically magnesium and calcium, followed by carbonates and bicarbonates are the main reasons for the unsuccessful breeding of many South American dwarfs (they don't care for salts). Putting too much emphasis on pH does not solve the problem since one can say that pH is a kind of symptom of the mineral content of the water, not the actual cause. When you think of breeding dwarfs, think TDS.
In addition, it is my understanding, though I have no technical data or proof on this, that the blackwater rivers in South America are low in TDS levels, and basically sport some of the cleanest natural rivers in the world. According to Mongabay, "blackwater rivers are very low in dissolved minerals and often have no measurable water hardness. The very acidic, almost sterile water, with a pH between 3.5-6, keeps parasite and bacterial populations to a minimum… often compared to "slightly contaminated distilled water… blackwater rivers are nutrient poor."
Whitewater rivers are richer in minerals compared to blackwater rivers, and often sport a slightly higher pH and are generally much more laden with minerals and nutrients. It is important to note that the rivers are not uniform and there can be drastic changes in water chemistry especially when comparing black-, white-, and blue-waters. "Because whitewater rivers are often fed by a large number of acidic tributaries, they are relatively soft in terms of water hardness due to their relatively low mineral content and have a slightly acidic to neutral pH (6.3-7.0)" (souce : mongabay).
 
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kribensis12

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Some time back while researching for an article on TDS, I came across this information which may be of interest. Source is:
Jensen, Niels (2009), “The Importance of Total Dissolved Solids in the Freshwater Aquarium,” as reposted on PlecoPlanet at http://www.plecoplanet.com/forum/showthread.php?t=3480

TDS and Low ph fish
As I stated earlier, when we talk of softwater fish or low pH fish, what we really are saying is that they are low TDS fish. Even though many of these low TDS fish have adapted to harder, higher pH water, (and often relatively higher TDS levels), there is one fundamental problem, especially for South American dwarfs : the eggs cannot adapt well in calclium and magnesium rich water, and cannot hatch. My own experiences tell me that high TDS levels (in my case, mainly due to high levels of calcium and magnesium ions) are the culprits. This is where I used to make mistakes. I would use different methods for lowering pH and hardness but would take no consideration of TDS values. Peat can solve this problem.
I now use peat to successfully lower calcium and magnesium levels and thus pH (as well as KH and GH), as well as TDS. Many of the dwarfs I tried this with seemed to be much more content and this was reiterated by their ensuing fry (cacautoides, apistos, ramirezis, and other S.A. dwarfs.
If you match your own water with the fish's natural water chemistry, keep TDS levels low. My own experiences have taught me that the mineral content of the water, specifically magnesium and calcium, followed by carbonates and bicarbonates are the main reasons for the unsuccessful breeding of many South American dwarfs (they don't care for salts). Putting too much emphasis on pH does not solve the problem since one can say that pH is a kind of symptom of the mineral content of the water, not the actual cause. When you think of breeding dwarfs, think TDS.
In addition, it is my understanding, though I have no technical data or proof on this, that the blackwater rivers in South America are low in TDS levels, and basically sport some of the cleanest natural rivers in the world. According to Mongabay, "blackwater rivers are very low in dissolved minerals and often have no measurable water hardness. The very acidic, almost sterile water, with a pH between 3.5-6, keeps parasite and bacterial populations to a minimum… often compared to "slightly contaminated distilled water… blackwater rivers are nutrient poor."
Whitewater rivers are richer in minerals compared to blackwater rivers, and often sport a slightly higher pH and are generally much more laden with minerals and nutrients. It is important to note that the rivers are not uniform and there can be drastic changes in water chemistry especially when comparing black-, white-, and blue-waters. "Because whitewater rivers are often fed by a large number of acidic tributaries, they are relatively soft in terms of water hardness due to their relatively low mineral content and have a slightly acidic to neutral pH (6.3-7.0)" (souce : mongabay).

That is very helpful and I think that the analogy of pH being the symptom, not the disease applies well here. The pH is they way it is due to the mineral content of the water. The higher the TDS, it seems, the more stable and likely higher the pH is.


I purchased a TDS meter this past week and out of the tap, our TDS is 450 and being in an aquarium for a week prior to the next water change (where excrement, food etc. occur), the TDS can be as high as 600.

This seems to reinforce an unfortunately really dumb thing I did as a 16 year old. I had angelfish and wanted to have a lower pH so I added a full tanks dose of Neutral Regulator (by Seachem) directly into the tank. To be fair, the directions didn't explain how to safely lower the pH where there are fish already in there.... The pH did indeed drop from 8.4 to 7.0 within an hour (YIKES!!!!!!!!) and due to our extraordinarily high kH and gH (evidenced by a TDS of of 450-600) it bounced back to 8.4 overnight.....

Praise the Lord no fish died from that swing -- but it did stress them severely and caused a massive Ich outbreak that killed some black mollies at the time.... I'll never, ever repeat that mistake again.

So @Byron and @Colin_T --> I've got a few tanks which pH I would ideally like to lower pH/Hardness. It sounds to me, that in my scenario - the best solution is to at every water change introduce water with a lower pH and overall TDS/hardness (R/O mixed with a bit of tap water) and over time, that will lower my pH in a tank friendly way - would you agree? I wish I could just throw some extra driftwood in there and call it a day, but our water is so hard that the tannic acid never makes a dent in the pH.
 

Byron

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Yes, the only way in my view to safely and effectively reduce GH and pH is to dilute the "hard" water with "pure" water, and maintain the same balance (hard/pure) at each water change. The tank's biological system will balance and remain there over time.
 
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