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Thread: Beneficial Green Water? A beginning of understanding

  1. #1
    Daihonmei MikeM's Avatar
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    Beneficial Green Water? A beginning of understanding

    Recently I have been catching up on studies concerning the microbiome of fish. Akai-san's revisting of his greenwater situation has nudged me to post about one aspect of the microbiome that I hope will be studied more and adds a new dimension to my thinking about greenwater. Rather than add a tidbit to the microbiome thread, I decided to pull together various thoughts about greenwater and start a new thread. So, what does the microbiome and greenwater have to do with each other?... Well, everything is inter-connected. So hang in and read on.

    First, my biases: Most everything written about greenwater focuses on how to get rid of it. As regulars know, I have been a bit of a contrarian… just a little. I have frequently mentioned how I stopped using UV several years ago and find that my pond remains clear (or, I should say, sufficiently clear to fully view and enjoy my koi even when six feet down at the bottom). A vaguely greenish tinge does appear on occasion, which I ascribe to disruptions in the efficiency of nitrifiers in the bio-film due to environmental influences… temperature shifts and the like. I view this not as a negative, but as an indicator that the greenwater algae are stepping in to fill the void and thereby benefitting my fish. My thinking on this undoubtedly influences how I view related subjects. The fact is, I do not view greenwater as a negative for our koi unless it is so flourishing that oxygen deprivation overnight becomes a real risk. That does not mean I think pea soup greenwater in our ponds is OK. I do not. There is a huge difference between the greenwater of a healthy mudpond and the greenwater in a putrid, pea soup hobby pond.

    Greenwater is a negative for enjoying the beauty of our koi, of course. That negative goes to the heart of why we keep koi, but it does not necessarily concern koi health. Indeed, in the pursuit of the ephemeral 'gin clear' water we may actually be creating a less beneficial environment for our koi. Sometimes there is no perfect balance between optimal enjoyment and optimal husbandry.

    It has long been observed that there are health benefits when koi are kept in greenwater. It has been said that hikkui can be 'cured' by placing the koi in greenwater. This is not true. It has been often observed that hikkui symptoms recede or even disappear entirely, but it is not actually cured. It comes back when the koi is placed in clear water, usually within 6-8 months. There have been many guesses about why greenwater retards hikkui, but no scientific evidence establishing the mechanism seems to exist. There are also many reports of wounds healing better in greenwater, bacterial fin rot resolving on its own when the fish is placed in greenwater and reduced parasitism. We have seen koi coming out of greenwater to have more brilliant color, more lustrous skin and robust healthfulness.

    Why is this? There are a lot of ideas put forward, although seldom supported by specific scientifically conducted studies. Nonetheless, they are logical ideas arising from science. One factor often mentioned is that the greenwater algae protect our koi from harmful sun exposure. Another idea recognizes the fact that single cell algae are pretty good at capturing ammonia in the water column. Since the single cell algae are floating around in the pond, they have an opportunity to capture any available ammonia as soon as produced. While the nitrifiers in our bio-filters clearly out-compete micro-algae (pun intended), that does not mean that greenwater algae are not doing a great job on their own. Their presence may well indicate that the ambient level is even lower than the 'less than detectable with my test kit' standard we hobbyists use. Another idea, is that koi, like certain filter-feeding carp species are able to consume the greenwater algae directly. Perhaps this occurs to some degree, but it seems more likely that micro-algae consumption by koi would be limited to aged, dying micro-algae, since it is these which tend to clump together as cell walls cease to be repaired. We have all seen these clumps as green slime captured in filters when there is a greenwater outbreak. Although the cell walls of algae have no significant nutritive content (largely non-digestible cellulose), the interior mass has substantial protein content and a full range of vitamin/mineral nutrient. We do know that chlorophyll enhances color pigments.

    Recent research in the fields of probiotics and the microbiome are adding scientific knowledge. The many studies in these fields touching on greenwater algae can be problematical. One researcher observes that there are over 32 genera of micro-algae commonly found in various areas of the world, with countless species. And, greenwater algae communities are typically composed of many species. There is seldom much effort put into identifying particular species (or even genera) when the focus of the study is on a particular probiotic bacteria. However some studies do make the effort. Among the findings of interest, there are many bacterial strains examined for use as probiotics in aquaculture that may have a significant algicidal effect on various species of microalgae. Of 41 bacterial strains tested, 23 inhibited the growth of the unicellular alga Pavlova lutheri to various degrees. (Making these potential probiotics contra-indicated where fish fry are being raised using unicellular algae, as in the typical koi fry mudpond.) And, there are several studies where positive effects on cultured microalgae were observed when various probiotic bacteria were added to the culture. In still other studies, greenwater algae were observed to have a bactericidal effect. Studies done in the Phillipines in promotion of aquaculture are particularly convincing. Their National Institute of Molecular Biology and Biotechnology (NIMBB) and the Institute of Aquaculture of the College of Fisheries and Ocean Sciences (AI-CFOS) of the University of the Philippines have worked on developing the cultivation of greenwater to attain greater production of shrimp. At the same time, much work was being done to prevent or control bacterial diseases which afflict shrimp production. The two lines of inquiry came together in the work of Dr. Jesse Ronquillo and Prof. Valeriano Corre Jr. pursued over nearly two decades. They developed techniques for producing controlled greenwater ponds by combining tilapia farming (which produces very green water) with the farming of filter-feeding shrimp. Recirculating systems give the shrimp constant in-flows of their greenwater food produced in tilapia ponds. They have found that their system was both very efficient in terms of resources required for the poundage of food produced, and also prevented common bacterial diseases afflicting the Phillipine shrimp industry. There was both direct inhibition of particular pathogens, and stimulation of the immune system overall. Other studies have established that greenwater environments, which we koikeepers consider unstable in terms of oxygenation levels and risks of pH shifts overnight, actually favor stable microbial communities with relatively few pathogens. Continuing research is beginning to identify correlations between certain greenwater algae species and repression of particular clades of pathogenic bacteria.

    The mechanisms involved are just starting to be identified. It appears that alleopathy is one mechanism involved. That is, certain greenwater algae emit chemicals that have a bactericidal or bacteristatic effect… they kill bacteria or retard bacteria growth/replication. These exudates have not been identified (in any study I have come across), but in time will be. It also seems that the interaction of greenwater algae with the microbiome of aquatic animals stimulates the resident beneficial bacteria to be more responsive against pathogens. The enhanced immune response may well be composed of both internal immune systems (T-cells and such) and the external microbiome becoming more robust.

    In the course of these investigations, it has also been established that the unicellular algae have their own microbiome. Their surface is the habitat of bacteria which seem to have beneficial interactions with the alga. It may be that the allelopathic aspect of microalgae combatting pathogens may actually be their microbiome bacteria combatting the pathogenic bacteria in protecting their little habitat on the surface of the algal cell.

    Perhaps in the next decade or two we will begin to learn just what is going on in our ponds. In the meantime, I think it is safe to say that the observations of benefits from greenwater are gaining scientific support. It is not just legend and folkways... even if not yet actually understood.

  2. #2
    Jumbo Akai-San's Avatar
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    Quote Originally Posted by MikeM View Post
    Recently I have been catching up on studies concerning the microbiome of fish. Akai-san's revisting of his greenwater situation has nudged me to post about one aspect of the microbiome that I hope will be studied more and adds a new dimension to my thinking about greenwater. .........

    We have seen koi coming out of greenwater to have more brilliant color, more lustrous skin and robust healthfulness....Why is this?
    Mike! OMG! Without me writing about my specific thoughts about how I have been watching my current algae condition/situation unfold, you have once again opened your book and shared great insight on the "green water" topic. Sorry if my post is a little off topic, but I think your post above touches on perceived benefits of pond algae.

    Sooooo, during my ongoing green water period (starting in June), I was witness to some surprising development of my QT koi. At the beginning of June, I took three koi (to be re-homed) out of main pond to make more space. I still did my weekly 15%-20% water changes and solids flushes, so I wasn't too concerned about the water quality. The algae plume happened over time in the heat and exposure of summer. My koi are not quality koi, but from the time I first inspected them (in June) and then bowling them recently, I did notice improvements in each koi's color and even plumpness in skin (not sure how to describe). I don't feed color enhancing food so it really made me think. "What the heck just happened??" Now I'm wondering if I should unplug my UV clarifier...and place a couple of my favorite koi in the green water. LOL!

  3. #3
    Sansai
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    Quote Originally Posted by Akai-San View Post
    Mike! OMG! Without me writing about my specific thoughts about how I have been watching my current algae condition/situation unfold, you have once again opened your book and shared great insight on the "green water" topic. Sorry if my post is a little off topic, but I think your post above touches on perceived benefits of pond algae.

    Sooooo, during my ongoing green water period (starting in June), I was witness to some surprising development of my QT koi. At the beginning of June, I took three koi (to be re-homed) out of main pond to make more space. I still did my weekly 15%-20% water changes and solids flushes, so I wasn't too concerned about the water quality. The algae plume happened over time in the heat and exposure of summer. My koi are not quality koi, but from the time I first inspected them (in June) and then bowling them recently, I did notice improvements in each koi's color and even plumpness in skin (not sure how to describe). I don't feed color enhancing food so it really made me think. "What the heck just happened??" Now I'm wondering if I should unplug my UV clarifier...and place a couple of my favorite koi in the green water. LOL!
    Could it be there is less competition in the QT,therefore more nourishment to go around?
    In the wild you seldom see gin clear water.
    I have always wondered why my fish are a LOT LESS inclined to feed in green water, they remain out of sight and only pop up for a look see and snatch the pellets now and again,never vacuuming food as they do when it is more clear.
    In gin clear water they are up and about hustling for food,why would that be?

    Garfield

  4. #4
    Daihonmei MikeM's Avatar
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    Quote Originally Posted by coolwon View Post
    ***
    I have always wondered why my fish are a LOT LESS inclined to feed in green water, they remain out of sight and only pop up for a look see and snatch the pellets now and again,never vacuuming food as they do when it is more clear.
    In gin clear water they are up and about hustling for food,why would that be?

    Garfield
    There are aquaculture studies about the different behaviors of fry and fingerlings raised in greenwater vs clear water. I'll see if I can find where I stashed them.

    Question: Do your fish in greenwater lose weight? Remain the same weight? Or, gain weight?
    coolwon likes this.

  5. #5
    Sansai
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    Hi MikeM

    I am really not that observant when it comes to those sort of tolerances.

    I am inclined to shovel food in.

    I do get very good growth. A skinny eel type fish in my pond has an eating disorder or is old and going on pension.

    I have a Soragoi which looks like modern man.

    I actually do not have a very good eye for future champions either.

    Building the pond was far more interesting to me

    Now that you mention it, it stands to reason they should slim down if they are not guzzling food.

    Cheers

    Garfield

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    Jumbo Appliance Guy's Avatar
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    I'm under the impression (right or wrong) that algae reduces the ammonia to a near zero level, and that this reduction is responsible for better looking skin.

    As a side note, anyone ever try to get their pond to 'go green'? I have, twice, with no success. I thought about what I can do to make it go green, and really, I couldn't think of anything. From my old days of growing greenwater (nannochloropsis) to feed brine shrimp (artemia), I reckoned I could explore this as a possibility, but I decided it could lead to something that I might regret later. I can't refrain from water changes and continued to preferm my weekly chore of a 10-15% change, and I continued to have a daily flow through of about 2-3%. Of course the UV has been off for almost a couple years and continues to remain off.

    Ultimately, I can't get my water to go green even if I wanted it to. I believe it is mostly because of my large shower with 400#'s of feather rock and 11,000gph going over it. I wish I could go green for like three of four months before a show, but I can't...

  7. #7
    Sansai
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    Quote Originally Posted by Appliance Guy View Post
    I'm under the impression (right or wrong) that algae reduces the ammonia to a near zero level, and that this reduction is responsible for better looking skin.

    As a side note, anyone ever try to get their pond to 'go green'? I have, twice, with no success. I thought about what I can do to make it go green, and really, I couldn't think of anything. From my old days of growing greenwater (nannochloropsis) to feed brine shrimp (artemia), I reckoned I could explore this as a possibility, but I decided it could lead to something that I might regret later. I can't refrain from water changes and continued to preferm my weekly chore of a 10-15% change, and I continued to have a daily flow through of about 2-3%. Of course the UV has been off for almost a couple years and continues to remain off.

    Ultimately, I can't get my water to go green even if I wanted it to. I believe it is mostly because of my large shower with 400#'s of feather rock and 11,000gph going over it. I wish I could go green for like three of four months before a show, but I can't...
    What sort of nitrate readings do you average?

    Garfield

  8. #8
    Daihonmei MikeM's Avatar
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    Quote Originally Posted by coolwon View Post
    Hi MikeM

    I am really not that observant when it comes to those sort of tolerances.

    I am inclined to shovel food in.

    I do get very good growth. A skinny eel type fish in my pond has an eating disorder or is old and going on pension.

    I have a Soragoi which looks like modern man.

    I actually do not have a very good eye for future champions either.

    Building the pond was far more interesting to me

    Now that you mention it, it stands to reason they should slim down if they are not guzzling food.

    Cheers

    Garfield
    Yes, but have they slimmed down? ....Many years ago, Peter Waddington told the story of an abandoned pond, emptied except for some shallow water in the bottom... and a bunch of junk that had been tossed in (or fell in). He went to clean out and re-start the pond, and found a perfectly healthy robust koi living in the opaque greenwater. No food had been given for untold months, but the koi showed no ill effects. He guessed it survived on insect larvae. I suspect that was partially correct, with the other part being consumption of the detritus formed by dead/dying greenwater algae. Unlike filamentous algae, which have a high proportion of non-nutritive cellulose, the unicellular algae have good nutritional content. Your situation is much different from a single koi left to fend for itself. But, I would not be surprised if over a period of a month or so any weight loss was not particularly noticeable.

  9. #9
    Daihonmei MikeM's Avatar
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    Quote Originally Posted by Appliance Guy View Post
    I'm under the impression (right or wrong) that algae reduces the ammonia to a near zero level, and that this reduction is responsible for better looking skin.

    As a side note, anyone ever try to get their pond to 'go green'? I have, twice, with no success. I thought about what I can do to make it go green, and really, I couldn't think of anything. From my old days of growing greenwater (nannochloropsis) to feed brine shrimp (artemia), I reckoned I could explore this as a possibility, but I decided it could lead to something that I might regret later. I can't refrain from water changes and continued to preferm my weekly chore of a 10-15% change, and I continued to have a daily flow through of about 2-3%. Of course the UV has been off for almost a couple years and continues to remain off.

    Ultimately, I can't get my water to go green even if I wanted it to. I believe it is mostly because of my large shower with 400#'s of feather rock and 11,000gph going over it. I wish I could go green for like three of four months before a show, but I can't...
    Yep. I'm with you on this, Tim. ....Destroy all your biofilm with repeated doses of PP and perhaps then you will get greenwater before the biofilm re-establishes itself??....I DO NOT recommend doing it.

  10. #10
    Daihonmei MikeM's Avatar
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    Back to Coolwon's observations of behavior/feeding changes in greenwater.... The studies I recalled referring to changes in fish behavior in greenwater are focused on hatchlings and fry of marine species, not mature fish and not carp. But, they are of some interest nonetheless. First, brief summaries of some of the studies, and then some thoughts of my own regarding Coolwon's observations:

    *Studies of Atlantic halibut larvae (hatchling fry) at the Austevoll Station in Norway (Naas, et al., 1992) demonstrated major improvements in survival when green water was used rather than clear water, but nutritional effects were considered minor in comparison to the effect on behavior. Halibut larvae in clear water concentrated at the water surface and near the tank walls. In green water the larvae spent most of the time in the water column, searching for prey. Some opine that attraction to light inhibited consumption of available food. An alternate idea is that green water alters behavior through its optical qualities. Research at Western Kentucky University (Salgado, 1992) involved rearing fathead minnow larvae in constant darkness versus constant light (all trials in clear water). Replicate trials in both settings involved feeding either live or ultrasonically killed brine shrimp nauplii. Dead nauplii provided only olfactory cues in darkness, whereas live larvae provided cues by their swimming movements. Visual cues were available in lighted conditions. Lighting and feeding regimes were, at a later stage in development, reversed in all treatment combinations and the relative food intake measured. The larval fathead minnows which had been reared in darkness displayed superior olfaction and acoustico-lateralis (distant touch through the lateral line) capability, compared to more visually oriented larvae which had been reared in constant light. Since day and night periods occur in nature and since feeding in nature tends to occur during daylight, the superior olfaction and distant touch capability of larvae from the dark treatment may have involved some artifacts of experimental design, since larvae in nature would be expected to have well-balanced sensory capabilities. Therefore, it was hypothesized that green water may obscure visibility to the extent that a better balance in the use of sensory modalities would be induced in fish larvae under those conditions, in comparison with clear water and unlimited visibility.

    *A series of studies (J.N.C. Whyte, Pacific Biological Station, Canada Department of Fisheries and Oceans) were done as rearing trials of the whitespotted greenling, kelp greenling, lingcod, tropical damselfishes, painted greenling and grunt sculpin. In clear water, larval halibut tended to swim cross-current into tank walls (i.e., bashing into the walls), and showed poor survival rates. The use of algae paste to reduce visibility resulted in slower swimming, active feeding and formation of schools, with higher survival rates. With the damselfish larvae, addition of algae paste caused immediate changes in larval distribution, bringing larvae away from glass walls of tanks and closer to the tank surface. Grunt sculpin and painted greenling larvae could not be reared in clear water, apparently due to wall-nosing by the painted greenling larvae and upward swimming at the surface tension film by grunt sculpin larvae. With green water, both grunt sculpin and painted greenling larvae became distributed more in midwater, with apparent increases in frequency of food intake, and survived to become juveniles. With whitespotted greenling larvae in green water, 75% of hatched larvae survived to the pelagic juvenile stage at 65-days age (posthatch), and 36% of the hatch survived to the settled juvenile stage at l20-days age. Mortalities among individuals which persisted in wall-nosing were associated with lower growth rates and significantly lower contents of those fatty acids which can be oxidized to provide maintenance energy, whereas the more structural essential fatty acids remained at constant levels.

    *In some instances green food coloring in skim milk was used rather than algae paste to increase turbidity. The effects of colored milk on behavior of whitespotted greenlings were similar to those of algae, except that the milk settled out from the water relatively rapidly and the fish larvae tended to become stained green. It was evident, however, that the turbidity effect of the algae, and not some biochemical signal, was responsible for the alteration of behavior.

    *The role of 'distant touch' (sensing through the lateral line) in schooling (Pitcher et al., 1976) has been concluded to indicate that the larvae tend to switch from more exclusively visual orientation to a balance between various senses when vision is limited by turbidity. There was immediate acceptance of frozen krill in green water, upon physical contact at the mouth (presumably based on gustation rather than vision), compared to pelagic juveniles in clear water only gradually accepting frozen krill, striking from a distance by vision. The Salgado (1992) studies of larvae feeding in light versus darkness may also be explained on the basis that in clear water in continuous light, the larvae would rely exclusively on vision, with the result that they fail to undertake schooling and tend not to encounter food items as frequently due to when they are nosing into walls. (The wall-nosing may indicate an innate tendency of greenlings to cross current shears when in clear water, in order to increase chances of encountering water masses with phytoplankton blooms and the associated blooms of edible zooplankton).

    *One writer reviewing the scientific literature suggests that clear water results in anomalies in behavior that in nature would lead fry toward turbid water, but in confined quarters results in reduced feeding. Across the studies, there was a uniform consequence of clear water… the fry swam more rapidly and headed to the walls or surface.

    What stands out to me in these studies is the idea that in greenwater fish use all of their senses more fully, while in clear water they rely much more heavily on vision. Since in nature carp are a bottom feeding fish, it seems natural that they would not come to the surface to find food unless drawn to it visually. There could be a learned response when sensing pellets hitting the surface of the pond. In the typical hobbyist pond, however, there are many noise sources (aeration, waterfalls and such) that could mask the sound and vibrations of pellets hitting the surface. Without the visual cues, they just don't know the pellets are there. I expect they would learn eventually to distinguish pellets hitting the surface from other noise/vibrations.

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