Understanding "Aeromonas Alley"

[Gazza]

Hi Guys,

So here is a question for you what is Aeromonas Alley and what does it do to effect our fish

How many times do you hear this come up in conversation that we have to be very careful of this especially at lower temperatures and how it can kill all our fish

There are many of us and newbies out there who hear of these things and then poo their pants thinking its something that will jump out on them and wipe out their fish at lower temperatures and you have to keep away from it so i thought i would get a little post going so we can see what peoples take on it are and if we have any ideas on why it happens and what we can do about it

So guys anyone seen it and what do we know about it

[Brockp]

Well Gazza you opened it up and I will stick my neck out;

To me "Aeromonas Alley" is that temperature range in our ponds (I would guess from 7 or so up to 15+) when nasty pathogenic bugs like Aeromonas and others nasty bugs including pseudomonas and range of others are happily reproducing but our fish's immune system has yet to start firing on all cylinders and they are potentially more vulnerable to infection.

As this occurs both in spring and autumn as our ponds warm up or cool down (unless your heated!) it is potential a twice yearly event. However in the autumn our fish are all well fed and healthy but in the spring they have just survived an English winter and are generally less fit and therefore it tends to be more of a spring problem.

Now I will duck

Peter

[tomy2ponds]

I have always done a pre spring check to make sure everything is spotless and there is no muck collecting any ware and that I do regular filter cleaning and water changes and have plenty of air going into the pond and filters also new UV tubes are fitted.The Koi also get a scrape and the water is tested regularly with a slow increase in food.I am unheated so the temp rise is slow.

[Gazza]

Hi Lee,

Are you saying that your only get Aeromonas only effect our fish at certain times or in dirty ponds

[tomy2ponds]

Hi Gazza if you have dirty filters or crap collecting somewhere in the pond system you could get Aeromonas bacteria so by keeping everything clean you can help to avoid it.

[Brockp]

Lee et al

I agree Aeromonas is a year round pathogen and the number one enemy bug which dirty pond would encourage. Aeromonas alley, if it exists I think refers to the water temperature when our fish are most at risk becuase of lowered immunity.

When I looked into this there seems no agreement on what that temp ban is. I have seen opinions that it is 4 - 9 and everything else in between. There is an article on it in this month’s Koi mag that has just arrived.

I guess the real question is “at what temp do our koi’s real immune systems real start to kick in”. I thought is it was about 15 deg ish!

Peter

[StuW]

Ok but I guess the most important question, and one that has already been alluded to, is how much is it affected by water quality. ie if my water is perfect and my filters working at the MAX for the appropriate temp are my koi at risk or is it really an issue for ponds with little or no overwintering maintainance.
Touch wood since I have kept good water the amounts of problems occurring in Spring/winter has significantly decreased.
interesting thread.

[Gazza]

Hi Peter,

I have not seen the Koi mag yet will have a look later it may the answers we are all looking for

Yes this is one of the reasons i started this going as there are so many options out their i thought we could have a bit of a chat to see what we all think we know about it all as its a good way to learn

I believe from text that i have read before that the bacteria we are talking about the Aeromonas will normally be able to replicate at 4c and get an optimum growth at 10c so i think these are the temperatures that can be of most benefit for the bacteria to "do their thing"

So you are on the ball with the thinking of at what temperature does the immune system of the fish be at its best to keep the bacteria at bay...but then again if the fish is OK then will there be any need to worry about the bacteria,will it attack the fish

[Brockp]

Hi Gazza

You are totally right. this group of bugs is "opportunistic" so if the fish are fine no parasites opening the door to let the bugs in things should be fine.

The interesting things is a lot of us who "semi heat" or warm our ponds during the winter hold them in the temp range that would favour Aeromonas.

Peter

[Gazza]

Hi Stu,

Yes water is always the key to the majority of the problems which happen in a fish pond and one thing for sure a dirty fish pond is never going to be a good place for any fish to be as there can be so many spin off problems just impacted by the bad water quality.

Many of the types of bacteria in our ponds are what is called (sorry i am going to try and remember some technical stuff now so someone will probably have to correct the spelling or names later when i cock them up ) saprophytic and are well known for being the nasty little ones which can cause harm to our fish but is this something they just do anyway or is there a reason behind this

These bacteria normally on a day to day basis will just not attack a fish willy nilly or for no reason but......yes there is always a but they will become a bit more opportunistic ( i think this is where they can change to be pathogens) when there is an injury or some kine of problems or low immune system and thats when they will infect the fish especially on a wound and i think many of us have seen what this looks like. the problem is once it gets going they just multiply and can make a lot of damage very fast and if left to long it can even lead to a fatality.

[Gazza]

Hi Peter,

I think we are on the same wavelength

Yes we can indeed by heating through the winter keep the bacteria nice and snug and doing their thing in a nice warm pond but a lot of the time they keep away from our fish and i wonder how many there are around our fish sometimes

[Brockp]

I actually have some pictures of bacterial colony counts from my small growing on pond. I will try and put them up here. It is quiet easy and interesting to follow the colony counts of the bugs using simple dip slide tests against bond temp. I am following my small pond weekly. I will post the results when i have a bit more data.

Peter

[Gazza]

Hi Peter,

Sound cool and will be very interesting

[Duncan]

Hi guys

I sometime leave threads to run with out intervening cuz I enjoy watching them develop so don’t automatically assume I’m not interested.

Aeromonas alley is a strange term to be sure I believe this term was derived in the states and refers to a set temperature window where bacteria are active but more importantly the koi’s immune system is asleep

I think you have covered the bacterial angle enough I have just a few comments that may help or not as the case may be.

Aeromonas are facultative gram negative anaerobes , which means it can function basically with or without Oxygen as opposed to obligate anaerobes which will die in the presence of Oxygen. Simply put being facultative rather than obligate means they can make ATP by aerobic respiration or they can make ATP by fermentation in anoxic conditions ( no oxygen) a kinda AC/DC of the bug world! Essentially for us this means they are not totally dependant on a dirty sludged up pond any more than they are a clean pond although the former is probably preferred.

Note: ATP Adenosine-triphosphate (ATP) is a multifunctional nucleotide used in cells, ATP transports chemical energy within cells for metabolism. And ATP is manufactured and is also used in koi


More importantly for us Aeromonas are heterotrophic which means they derive the nutrients for carbon material hence why they like fish so much but this can also mean they will like area’s of the pond with high organic build up but like wise this can mean high DOC’s for feeding which is why it important to keep these and obviously your TDS to a minimum


The other thing is those bacterial dip slides will be measuring all bacterial species so are no indication of the presence or growth of Aeromonas its just a general indicator and certainly a large % will be harmless and sometimes useful bacteria.


Regards the fish immune system start point , its not that back and white I wish it was , the fishes first line of defense is the cuticle ( mucus/slime coat ) this is not just a physical barrier like skin is to us , it contains all kinds of anti-parasitic and antibacterial materials in its own right , further the koi has a sophisticated immune system just like you or I, in many ways more sophisticated being as there is no bone marrow or lymphatic system, but its this side of the immune equation that fails the lower the temperature .trouble is it not like throwing a switch and switching a light on or off, it fails at varying degrees at various lowering temperatures. I put the figure where the immune system is still functioning to an acceptable level but obviously not as you would like at 12c. Below 12c it starts to falter very fast above 12 c it will strengthen and the higher this figures gets the more robust the immune system gets

If you were to ask me for a winter heating figure that would keep you koi safe and functioning I would there fore put that figure at a minimum of 12 c in fact except for this year this is the figure I have strived for as a happy medium for cost and efficiency

Ups and downs

The biggest problem for us is temperature bounce and instability and this is where heating pays dividends. What this means is if we can keep the temperature stable even a low temperature is far more beneficial than trying to attain higher natural temperatures but not being able to maintain it, so the vulnerable time for fish in Aeromonas alley is perhaps late spring when ponds start heating up a little but are capable of dropping severely the next day or at night what this does is keeps continually switching the koi’s immune system on and off while the bacteria just do what they do at any temperature but with an immune system that’s not anywhere near its best. So there is an argument to heat the pond at 12c up to Christmas , then in early January when winter temps drop like a stone and stay down turn the heating off and keep bacteria and koi down and stable then as spring approaches and temps rise but are not stable turn the heat back on a again to stabilize and keep the status quo

What I’m saying is Aeromonas alley lies below 12c, to varying degrees and sometimes when instability exists above 12 c

[Gazza]

Hi Guys,

I have always when asked do i heat my pond said i prefer to call it temperature controlling and that is for the similar reason Duncan has just said on his post about ups and downs as i like to try to keep the environment for the fish stable. I like to keep it stable not only in heat but also in a good water quality with a low TDS as in my mind having these conditions my fish will be far more healthier than if i had a dirty pond with a fluctuating temperature.

I have found in the past even going back to my old unheated pond that my fish where very unhappy in the colder months and would sit on the bottom and of course this in itself can cause sores and problems and these are the types of conditions the opportunistic bacteria thrive on. It was also apparent to me on how quick things can change as the temperature drops and that the fish would be great around say as we are coming out of summer and they have been in the higher temperatures and coming down from say 20c to say 15c would see very little change but noticed when you started dropping below the 12c mark things would defiantly slow up faster than in the higher temperatures. This is where i started to take notice and then with the new pond build decided to install heating so i could control this to try to find a minimum temperature that the fish would be happy with and didn't cost me a fortune

On the first winter as the pond was new i kept in fairly high to make sure the pond had a good chance of maturing and this would hopefully give me a good starting point leading up to the summer for the pond to be well on its way to maturing as the pond was up and running in October. What i did notice over the next few years was the difference a degree or so can make if it was going down toward the lower side around 10c ish. I now keep my pond at 12c through the winter as i found this was for me the best temperature for the fish and they are still nice and active and seem happy enough to do their thing and come out of winter (touch wood) in great condition.

This has not all been plane sailing as a few years back i did decide i was going to try lower the temperature to see if the fish will still come through the winter as well but of course to see if i could save a few £££££ This was all done as normal and the temperature was gradually drooped down and the food slowed down until it was at 10c and the fish did look OK and was fine so on went the cover and i waited to see how they went over the winter. I would as i always do pull the covers back when i could and try to keep an eye on them (i hate the covers ) then as spring came the covers cam off more and the fish looked OK. I then removed the covers as the weather was warming up and again all the fish looked OK although i had still not had any out and i noticed my chagoi looked a bit fatter Well within a week i could see she was defiantly getting bigger and then she was netted and on inspection she had a big sore on her belly which was very nasty she had obviously been sitting on the bottom and rubbing and this had ended up in a nasty ulcer and unfortunately i had caught this to late and she never made it

Lesson learned for me was that 10c was to low for me and that the covers are a pain and need to try to keep an eye on them beforehand and all through the winter is you cant see through the covers and ever since then i have carried out the same routine and kept it at 12c until it starts to warm up and get my head under them covers as often as i can