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Thread: pH and its influence on aquatic life

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    pH and its influence on aquatic life

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    Most of our real knowledge of the influence of pH in our tanks is not very scientific, and tends to be highly anecdotal. That's fine, as long as we learn the right things from the anecdotes.

    pH kits have an enormous markup, and shop owners love to sell them to newbies. They have a dozen atlases and other books, written mostly by chemical illiterates, to back up all kinds of mythology on the subject.

    When you jump into a swimming pool, ocean, or river, can you tell what the pH of the water is? Well, guess what, the fish can't tell either. Years ago, in his Killifish Atlas, Scheel described that pH shock was pure myth. My personal experience agrees with his, and any pH between about 3 and 10 is tolerated by most fish. I have never, in over 50 years of keeping fish, seen any effect of pH shock alone. I routinely subject killies to sudden changes of 2 or more full pH points. [Scheel mentions 3 points.]

    I have seen fish damaged by sudden movement from hard alkaline water to soft acidic water, but the injury was invariably from cellular osmotic pressure regulators not being given time to readjust.

    Going the other way can cause damage if there is a lot of ammonium (NH4+) in the water, and the increase in pH converts some of it to ammonia (NH3), causing severe burns to gills and maybe even skin.

    I have a couple of pH meters. They are far more accurate than a titration test, and quicker to use. Nevertheless, they hardly ever get used. I find that many of the things we used to blame on pH are due to entirely unrelated phenomena, and even the related ones, like the ammonium-ammonia ratio are best measured by themselves.

    In the planted tank, a lot of the pH mythology gets carried to a high level, but I, again, can't find any real dependence on pH among plants. Like fish, they are very sensitive to the various electrolytes that make up their internal fluids. Sodium is an essential to life, but quickly becomes toxic if there isn't enough potassium to enable proper transport across cell walls.

    Some plants need a little Ca and Mg in the water column, too, as well as smaller amounts of trace elements. Fish are the same way. I hate to tell you of the number of discus I have seen killed in LFSs by trying to keep them in pure RO water. One feeding of brine shrimp can introduce enough sodium to turn them black.

    I like to keep some tanks a bit on the acid side. That is hard to do if the water is hard, as the Ca and Mg are usually in the form of carbonates/bicarbonates that buffer the pH high. Peat and oak leaves are good at lowering the pH of softer water (e.g., tap water diluted with distilled or RO), and their humins tend to be fairly antibacterial. This has enabled me to breed certain wild Bettas and some rainforest fishes that otherwise are too sensitive to the bacteria living in more normal waters.

    I use my tds (Total Dissolved Solids or conductivity) meters very frequently, as changes of over 2X can cause real problems if not done slowly, particularly in the downward direction (hard to soft). I have heard of guppies jumping from a fresh water to a salt water tank with no visible harm. IDK how true it is, but dehydrating the gill cells certainly seems less damaging than bursting them by going the other way.

    When your fingers "prune up" from being in fresh water too long, it is the cells swelling from excess water being forced in by osmosis, while your blood supply cannot take it out fast enough. You don't want to do that to fish gills, that are much more delicate than your finger skin. Acclimate slowly if the new water is much different in tds.

    The bottom line, for me, is to be sure you understand a little about the water chemistry and the true role of pH.

    pH can be a wonderful way to measure the amount of CO2 you are getting into your planted tank (if the only buffer is carbonates), and it can be a warning about ammonia toxicity if you know the water has ammonium.

    Most other measurements of pH are a basic waste of time, and can be downright misleading sometimes, IMHO.

    That's my US$0.01 ($0.02, adjusted for inflation). Your anecdotes eagerly awaited, here.

    Wright
    01 760 872-3995
    805 Valley West Circle
    Bishop, CA 93514 USA

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    Great post, Wright! Very informative.
    Deborah

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    Wright, your post is highly educational but does it mean that what we hear often about certain fish preferring different Ph conditions are also myths. For instance, Chicilds are known to prefer alkaline water while Discus are known to do better in acidic conditions. Are these myths too?

    Loh K L

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    ....does it mean that what we hear often about certain fish preferring different Ph conditions are also myths. For instance, Chicilds are known to prefer alkaline water while Discus are known to do better in acidic conditions. Are these myths too?
    Yes and no. Wild fish from soft acidic water do very poorly in hard alkaline water and this is in part due to the bacteria they have brought with them.

    Bacteria manage to stay alive by creating a gradient of H+ accross their membranes. The generate H+ inside and then pump it out. The influx of H+ is then used to generate ATP for energy. In acidic water there is already a lot of H+ in the water and bacteria struggle to pump enough out of their cells to stay functional. They cannot simply rely on the external H+ but also need to generate basic building blocks from sugar etc... This process creates the internal H+ so eventually they are saturated both inside and outside with H+. The low cellular H+ is also bad for them as it denatures their proteins and enzymes (the same way how lemon juice will "cook" fish meat). So, when you take cardinals from the acidic amazon and put them in alkaline tanks the bacteria on thier skin that was battling to survive are suddenly given a chance to multiply rapidly. For this reason cardinals are generally treated with an antibiotic like ampicilin when they arrive from the exporter or kept at a low pH and gradually raised to a higher one so their immune systems can adjust.

    As for alkaline cichlids prefering alkaine conditions... my Neolamprologus pulcher Dafodils were spawning very happy in water that was dissolving my snails. The addition of some shell grit saw a flurry of carbondioxde bubbles rise to the surface.

    Given enough time fish adapt well to changes in salt concentration and pH. For ph the problem may be more immunity when going from low to a high; and tissue damage when going from high to low. The mucous fish secrete is also a natural buffer.

    With hard water fish it is the mineral salt concentrations that are so NB as Wright points out. For soft water fish it is the [NH4+] and maybe other factors.

    The bottom line is that it is not wise to make sudden changes to teh fish' environment. It takes a lot of energy for the fish to adapt and very often sudden changes can destroy the kidneys with overwork.

    There is a lot of myth regarding this topic. I for one have never used a pH test kit... in fact I have never owned any test kits. But putting this aside it must be said that myth grows from unexplained facts.

    Cheerio

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    Quote Originally Posted by timebomb
    Wright, your post is highly educational but does it mean that what we hear often about certain fish preferring different Ph conditions are also myths. For instance, Chicilds are known to prefer alkaline water while Discus are known to do better in acidic conditions. Are these myths too?

    Loh K L
    I believe fish can adapt quite well. Most discus keepers nowadays in Singapore do not really monitor the pH of the water as most local discus now can thrive in clean tap water. Some do not even use dechlorinators and still have their discus spawning!

    By the way Mr Loh, the cichlids you are referring to must be African ones and not cichlids in general.

    Yeap Wright many a times I've read of people who profess having a spawn after a drop in pH and such. So it may be just a coincidence?

    And yeah you are definitely right about the prices of these test kits. For the fish I buy the test kits cost more than the fish themselves

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    Yeap Wright many a times I've read of people who profess having a spawn after a drop in pH and such. So it may be just a coincidence?
    How did the pH drop? Soft water water change? Add some peat? Peat has antibacterial properties as well as other hormones that may trigger spawning.

    I have witnessed many spawning after water changes as regards my Ancistrus and Kribs although personally I have never correlated it with a pH drop.

    Maybe the pH drop serves to "tickle" the pair into action.:-)

    Fun stuff aside, I know there are many S.American cichlids and other fish that will only spawn when the water is just right and pH is a factor. But Wright it correct, pH isn't a killer unless the problem is already there (NH4+).

    Cheerio

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    Tyrone,
    Not all of us are well versed in chemical symbols. I, for one, am chemistry-handicapped and will appreciate knowing what is H+, ATP and NH4+

    Quote Originally Posted by TyroneGenade
    Add some peat? Peat has antibacterial properties as well as other hormones that may trigger spawning
    I've heard it said so often that I'm starting to believe it but has the antibacterial/hormone aspect been scientifically proven or is it propagated urban myth?
    I'm back & keeping 'em fingers wet,
    Ronnie Lee

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    Hello Ronnie

    H+ = hydrogen ion that is what causes acidity.
    NH4+ = ammonium ion, that is the less toxic form of ammonia NH3
    ATP = Adenosine TriPhosphate that is the uneriversal energy currency of the cell.

    I know the antifungal properties of the Sea Almond Terminalia
    catappa
    has been scientificly tested and found to be true. I suspect it has also be shown for peat moss but I'm not sure... I know the polyphenols in peat extract as well as being great antioxidants also interfere with bacterial metabolism and cell coats. I am however unable to give references for these claims...

    In Scheel's ROTOW he showed that the peat definetly encouraged spawning and sexual maturation of the fish he was working on.

    Cheerio

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    Quote Originally Posted by Joshua
    By the way Mr Loh, the cichlids you are referring to must be African ones and not cichlids in general.
    Joshua, I should have added the word "certain" to Cichlids when I wrote that sentence. I was thinking of those from Lake Malawi or something.

    Loh K L

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    I will agree with Wright and Tyrone,although the first time I read one of Wright's articles, I think it was in killitalk when I first read Wright's view on pH. I thought maybe Wright was off his rocker! :wink: I was shocked ...for all my fish years I always thought pH was as important as the water changes. But curiousity got the best of me and I decided to see for myself.....only to find that Wright was on his rocker!!
    I am now free of pH tests but sold on Equilibrum,for I get a reading of 30 TDS from my tap water. Summary..... healthy plants and fish
    Deb Bear
    AKA#08746
    SAA#175

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    Some of my fish practically thrive in low pH waters. I had a bunch of little Boraras rasboras that I picked up over the weekend at the last gathering and they were colourless. I placed a few in my main tank, where the pH is 6.0 to 6.4 and they immediately coloured up. Those that went in as dithers for my apistos promptly coloured up as well. I am certain that pH does play a role in maintaining the vitality of the fish as well as being a trigger factor in breeding successes.

    As is with guppies, when I placed these in my main tank, many died within half an hour to an hour after being introduced (these were acclimatised slowly to the water). Now this came as a shock to me since I thought they were so tough they'd be able to handle the lower pH in the tank. How unfortunate this assumption was. I now have a bunch of wild-caught "drain" guppies in a guppy tank I set up for my mum. The water is roughly about pH 7 and above since its purely from my tapwater (which is around pH 7.4) and the guppies have shown no problems. In fact they have multiplied in numbers from the original 10 I had.

    pH however isn't the only factor when it comes to triggering a spawning. In my experience with Corydoras, I have found that with a stronger water current and a fluctuation in both temperature and pH of the water, they will begin spawning, especially when it rains.
    Fish.. Simply Irresistable
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    Some of the responses here have borne out my original contention that what we think we "know" about the influence of pH is mostly anecdotal.

    I believe low pH accompanies beneficial conditions for breeding some fish. I hestitate to say it is the cause though, because I believe the humins and their antibacterial action are far more important.

    I have bred Neon Tetras in a tank that was clean, but had water at a pH of 7.8 and 450 ppm tds. 300 ppm was as CaCO3, or about 17 degrees of hardness! C'mon. These are Amazon fish that must have soft water to survive. Nobody bothered to tell my Neons, and I honestly have never been able to prove they can feel pH any more that I can.

    I do use a splash of very cold water to induce otherwise ready catfish to spawn. They could care less about what the pH is, "It's raining!"

    "Post hoc, ergo propter hoc," is the fancy Latin name for a simple and common fallacy in logic. It means "After this, therefore because of this."

    "I put the fish in softer, warmer, peat-filtered water that had a lower pH. Obviously the low pH made them spawn!"

    Sorry, but I don't buy that kind of argument. One must isolate the variables to make any observations that are meaningful.

    Why do I believe peat is antibacterial? Many observations of eggs doing better in peat extract have helped, but a totally outside thing convinced me.

    Some folks wanted to prove how much more sanitary their smooth plastic cutting boards were than the old-fashioned wood ones. Test after test showed far higher bacteria counts on the plastic than on the wood. The cellulose and humins in the wood were a natural antibacterial, just like many organic dyes are. Peat is just a shredded woody material that has been altered beyond any further decay. [Can't say the same about most of the coco fiber we can get here. ]


    Wriight
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    Wright, the majority of neon tetras in the trade now are farm-bred specimens. These buggers have learnt to live in far higher pH situations than what most people have expected. I have kept many for several years in tanks where the pH was slightly above 7 and none seem worst for wear. In fact they grew even bigger.

    People tend to believe alot in the power of pH when it comes to breeding fishes and some of it is quite true. You may feel its pretty absurd to tie down every breeding success to pH but without those low pH values, has anyone been able to keep AND breed the blackwater-dwelling anabantoids and cyprinids of tropical Asia? I have not had success keeping wild bettas or licorice gouramis in my tap water but they survive when I place them in tanks with aged and low-pH waters. This is not anecdotal but more of a personal observation. Not all species thrive in low pH waters however. A good example would be Betta simplex, as mentioned by Nonn in a previous post on the Non-Killie Section.

    When I used to have angels, I would trigger them to spawn with some blackwater extract squirted into the water. I didn't bother with the dosage so I just squirted enough to get the fish excited. Obviously the extract did something to get them in the mood and I was rewarded with several spawns a few hours after I added the extract to the water. This method was used several times to induce my other species to spawn as well.

    With regard to peat, if it was anti-fungal in property then why do I see a furry mould develop on peat in a container? Surely the anti-fungal properties of the peat would have kicked in and knocked the mould out of business right? Strangely though, it didn't and from time to time I find fuzzy bits of mould growing on a previously microwaved batch of peat moss.

    Quote Originally Posted by whuntley
    Peat is just a shredded woody material that has been altered beyond any further decay.
    Now I thought peat was more of a decayed form of sphagnum moss rather than decayed wood. Hmm.. you must be referring to the stringy wood fibers like those from Germany. I have some of these and they're certainly different from what we have here locally.

    I agree with your idea that low pH accompanies beneficial conditions for breeding some fish but rather than the humins and the anti-bacterial actions, I believe its more of the hormonal factor at play here. It has been mentioned several times that the hormones that peat releases into the water has been beneficial to fish more than it has been to plants. I have grown Cryptocorynes in a peat moss base substrate topped up with normal gravel and it has proven to be a good source of nutrition for the plant. From what I recall, the packaging on the bottle of blackwater extract made by Tetra says that the extract contains hormones beneficial for the well-being of fish and plants and helps to induce breeding. In my breeding experiences using the extract, it has proven, at least to myself, that it does work wonders when it comes to triggering spawnings. A friend of mine has used this product to good effect when it came to spawning his Corydoras hastatus.

    Quote Originally Posted by whuntley
    I do use a splash of very cold water to induce otherwise ready catfish to spawn. They could care less about what the pH is, "It's raining!"
    Now this is one thing I agree with. Indeed, they couldn't care less when the temperature gets chilly and there's a current of water running through the tank. Its just time to make babies.
    Fish.. Simply Irresistable
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    for peat's sake...

    Stormhawk:

    Now I thought peat was more of a decayed form of sphagnum moss rather than decayed wood. Hmm.. you must be referring to the stringy wood fibers like those from Germany. I have some of these and they're certainly different from what we have here locally.
    I've wondered about the differences of German peat and what's available in the US, which is from Canada: Baensch Book 1 cites filtering with peat when keeping A. australe. Naturally, if they are using the long-fibered peat (yes, available through LFSs and online by Hagen and gorgeously expensive for what you get) would it be a kinder, gentler cascade in releasing tannins, dropping ph? Even the Jiffy peat pellets I use are messy (looks like pipe tobacco in a bale once expanded) which I drop in barrels to "season" my Huntsville city water. Tony Terceira sent me eggs packed in this peat which he tells me his German friends use for packing material like we use styrofoam peanuts! Must be cheap and plentiful over there....

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    Jianyang,

    Peat is anti-bacterial, not anti-fungus.

    Quote Originally Posted by stormhawk
    With regard to peat, if it was anti-fungal in property then why do I see a furry mould develop on peat in a container? Surely the anti-fungal properties of the peat would have kicked in and knocked the mould out of business right? Strangely though, it didn't and from time to time I find fuzzy bits of mould growing on a previously microwaved batch of peat moss.
    I do not recall ever saying that peat had the slightest anti-fungal properties. It is trivial to see that it doesn't. Leave some damp peat lying around with some dead worms or other organic food. White fuzz develops rather quickly. Dead (infertile?) eggs also fungus very readily in peat. If you don' have a good supply of horse manure, it makes a fine substrate for growing mushrooms!

    Except for tuberculosis, which is a bizarre mix of fungus and bacteria, the two are quite different, with fungus more in the plant kingdom and bacteria in the animal, I think.

    Quote Originally Posted by stormhawk
    Now I thought peat was more of a decayed form of sphagnum moss rather than decayed wood. Hmm.. you must be referring to the stringy wood fibers like those from Germany. I have some of these and they're certainly different from what we have here locally.
    Sphagnum is a rather woody form of moss, and the fibrous stuff from Germany is just a reject from the process of producing agricultural peat. The decay is under cold highly anaerobic conditions, leaving the physical structure nearly unaltered.

    Except for on misleading labels, like Tetra's, blackwater and peat extract don't have any trace of hormones, AFAIK. Hormones are a product of animal glandular processes and the equivalent of hormones in plants are unlikely to have a lot of effect on a fish. Can you point me to a reference that will straighten me out on this? [As you can tell, I'm a member of KL's Sceptic group when it comes to fish-store hyperbole. ]

    Wright
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    805 Valley West Circle
    Bishop, CA 93514 USA

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    Wright, I'll try and find a source of info on this bit. They mention nothing about hormones but they sure say that it helps in getting fish to spawn. I'm going to the LFS in a few minutes time so I'll get back to you ASAP once I've gone through what's stated on the labels and other products.

    Found these links while I was surfing. Very good information listed.

    Peat Page by Niels Jensen

    Effects of pH on Fishes by Randy Carey
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    Stormhal said:
    Wright, the majority of neon tetras in the trade now are farm-bred specimens. These buggers have learnt to live in far higher pH situations than what most people have expected.
    Learning? No. Evolved? Yes.

    The ones that bred at fish farms succesfully had a genetic compliment that aforded them a reproductive success. Maybe their fry were less sensitive--had a better immune system able to resist the new bacteria they found themselves exposed to at higher pH values... The farmbred fish are tougher because with successive captive breedings and adaptations they have evolved to meet the aquarium environment.

    I have not had success keeping wild bettas or licorice gouramis in my tap water but they survive when I place them in tanks with aged and low-pH waters. This is not anecdotal but more of a personal observation.
    Again, I believe the problem is bacteria. The low ph combats bacterial growth. Move the fish to a higher pH and they quickly get diseased and die. If you had to raise the pH gradually you would find that your low pH loving fish will survie well at pH 7 after their immune systems have adapted. Treating with a broad spectrum antibiotic will kill the bacteria and so the fish wont develop immunity to the pathogens.. this is the route of the socalled "Discus plague" that doesn't really exisit. It is just fish being exposed to bacterial pathogens they are unfamiliar with at pH values where the bacteria can thrive.

    This is of course only a crude mix of second hand information, anecdotal observation and logically unsound hypothesis.

    Cheerio
    [/quote]

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    This is a fascinating thread!
    Deborah

  19. #19

    Water PH

    The PH of the water is very important if you're interested in the CO2 content of the water.

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    pH can be an indicator of how much CO2 is in the water. Ultimately it the hardness that matters. If there is a lot of calcium or magnessium in the water then you will have very little free CO2 as most will be bound as CaCO2 or MgCO2 which are both insolubale salts. In soft water a lot of CO2 can dissolve into the water but the more CO2 the lower the pH given the illusion that low pH water will hold more CO2.

    The ideal is to keep the water buffered around 6 to 7 with CO2 and have nice soft water. Back in SA I didn't have to bother with CO2 injection as my soft water allowed a lot of dissolved CO2. All I had to do was keep the surface turbulance low so the CO2 would not come out of solution. My Hygrophylia polysperma were growing in excess of 10cm per week and the submersed Indian fern was pushing out bubbles of O2.

    tt4n

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