Cloudy Water & Protozoa

An earlier post on the Nishikigoi International magazine's web board got JR to thinking. Fortunately, he was located near his keyboard when this happened!

Re: Cloudy water episode as the hetertophic bacteria has a "party".

Posted by James P on 6/9/2002, 1:04 am , in reply to "cloudy water episode as the hetertophic bacteria has a "party"."

If the group will forgive me, I would like to revisit a favorite rant of mine to answer Jeff's question. Water is clear, odorless ( hopefully!) and tasteless. But it is not void of life! In our ponds, water is "real estate" that can be a home for millions of micro organisms, algae cells and/or competing forms of bacteria. In a balanced pond this mix within the water column is resolved and constant ( at least seasonally). But disrupt the balance, or wipe out the current occupants and a new battle for turf is undertaken. So when you over do it with PP treatments for example, you can easily get green water. Or over dose with Formalin and the water may get cloudy for a week as the competing bacteria goes through a boom -bust cycle in a frantic effort to fill the niche or oxidize a newly created food source. The koi, by the way, will have no choice but to go along for the ride. Good water deteriorates constantly due to normal metabolic activity. But wipe out some of the microbes and a new balance must be established immediately. We are all aware when this happens to the biofilter bacteria. Traces of nagging nitrites and spikes in ammonia levels are measurable. But on another level, green water, cloudy water and dying algae on the pond walls place other toxins in the water which can only be observed in the appearance of the water or by declining oxygen and ORP levels. Most pond owners don't appreciate how important it is to preserve the water's balance once the pond is one or two years old and out of the new pond syndrome period. The example of pulling the plug on ozone is a reference to a change in the balance of the established micro fauna and flora of the pond water.

JR

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As if we haven't talked enough about Costia!

Posted by James P on 6/9/2002, 2:49 pm

Hi all, had a few off line chats with a couple of NI contributors and lurkers and wanted to add another thought about costia, chilo and protozoa in general before moving on. Protozoa are a real potential problem for our koi in a closed system. This group includes the big four- Costia, chilodonella, trichodina and Ich, as well as a half dozen other less common ones. Protozoa are not obligatory parasites (argument can be made in the case of ich). The group Ciliophora, of which chilodonella is a member, are not even considered true parasites. It is the numbers of individuals that lead to damage and secondary disease.

Because protozoa live in the environment in small numbers relative to numbers of koi in the mud pond, no epizootic conditions prevail. And within this loose relationship, koi develop an immunity towards those protozoa they are conditioned to. This immunity comes in the form of chemical composition of the slime coat and active white cells within the slime coat. But this immunity applies to only those species and subspecies that the koi is conditioned to. And this line of defense is only present when the koi is strong and not immuno-compromised due to things like stress and poor water conditions.

There is another dynamics that occurs that all hobbyists should be aware of and may account for stories of standard treatments not working or "resistant" strains of protozoa. When koi are exposed to NEW protozoa subspecies that they are IMMUNOLOGICALLY NAIVE to, the normal defenses are useless. Couple this with poor water conditions or some other event that is immuno-surpressing and you have a severe epizootic event. This is not unlike the bacteria infected koi that has no immune system and a hobbyist keeps injecting but gets no results. Is it the wrong type of antibiotic or is it the fact that the koi has zero resistance to the bacteria due a immuno-supression? It is usually the latter. There can never be zero aeromonas or pseudomonas in a pond. Only very low counts of these bacteria living side by side with very strong (immunologically speaking) koi. There can be a very similar dynamics when new protozoa are introduced to a weaken koi. Mixing koi from different countries with a reasonable quarantine period as an example, might be dangerous.

So to stick a fork in this subject and call it done - protozoa are likely always present in tiny numbers in many ponds. I like to call them "white noise" in the biology naturally found in most ponds. It isn't the mission of a koi keeper to treat the pond constantly "just in case" one trichodina lingers in the depths. Strive to create an environment that favors a strong immune system and one that doesn't favor protozoa reproduction. If symptoms are observed- treat the koi. If a random free-swimming costia is found in the filter bay, YES! I've checked and they can be there!!) don't trash the system trying to wipe it out! Generally speaking we want NO parasites in a closed system. Practically speaking, a ZERO level of protozoa species is probably impossible to achieve. We want them to be rare and "endangered" in our ponds. But they will never be extinct. And as usual, quarantine is the best line of defense.

JR

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