Mystery deaths

[peaches]

I set up my 200L planted tank at beginning of January moving across stock, substrate, plants and my Juwel internal from my 125L. I also added a U4 filter as it came with the new tank. Its running at 24 degrees. Latest readings pH7.5 NH3 0 NO2 0 NO3 5 KH 4 GH 15. The only readings that differed from Feb and March are the KH which was 6, then 5 and the GH which was 16 then 15. I change a third of the water weekly.
I keep losing the odd fish. At the rate of approx 1 a week. The fish that go are either platy, or cory. They do not have any signs of cause of death, but I thought the platys got thin. In the period of the deaths I have used protozin and myxazin. This week I used NT Labs Anti Fluke and Wormer. I thought that would work and after adding it many fish had stringy poop. But alas not. I am missing a platy today, no body turned up.
How do I stop the deaths?

 

[peaches]

I couldn't work out if this was water chemistry or fish tbh.

 

[shangman]

I couldn't work out if this was water chemistry or fish tbh.

It could be either, sometimes it seems fish catch things after a stressful event (like moving tanks) which suppresses the immune system enough for something already living relatively inertly in the tank or in the fish to take over.

Symptoms like stringy poop and thinness imply a stomach parasite of some sort, so I would treat for worms with Esha NDX first and see how that goes. I have been recommended Esha Optima before by a fish vet to help get up fish's immune system, soi would treat with that too. I would also feed more live food if possible to help with their health.

There is also a possibility of fishTB, but it has many symptoms so it's often on a list of possible illnesses (thinness, stringy poop, dying one after another). FishTB can be caught by people putting their hands in the tank and is apparently painful, so while you are working out what is afflicting your aquarium, you shouldn't share equipment between tanks(it can spread this way), and you must not put your hand in the tank if it has any sort of cut or scratch on it, and ideally wear gloves.

 

[peaches]

Fish TB, yes I've heard of that. I will try and be careful as I have started a couple of breeding tanks, no stock transferred. What is strange is it seems to affect some but ignore others. In particular I have a 3 year old otocinclus who seems bomb proof.

 

[peaches]

Does anyone know how long TB can be in a fishes system before causing death? I want to know if I can consider after x weeks or months of the deaths stopping that I am clear, or if I should regard this tank as being infected forever?

 

[shangman]

Have you treated for worms already then? Just cos it's better to rule that out first before assuming TB.

Does anyone know how long TB can be in a fishes system before causing death? I want to know if I can consider after x weeks or months of the deaths stopping that I am clear, or if I should regard this tank as being infected forever?

It's a difficult question, I have done a lot of research on it recently as my tank caught it and it was rather grim. My fish had a wider range of symptoms than yours though that made it more likely. From what I read, mycobacterium (which cause fishTB) can and do exist in a tank with fish for years and do nothing, and they can kill over years, months, weeks and days, some fish it may never effect. The worse it is, the faster it kills. There are several types of myco which kill at different rates, and only one in a fish tank seems able to hurt people. Of course that's the one that's most likely to kill the fish too so that's why caution is important here.

Personally in my tank I decided to euthanise all fish, thoroughly clean all equipment and start again, but I had a bad outbreak which seemed to have no end as fish continued to die and suffer (in my case every 3/4 days a new fish would get a new symptom and go downhill very fast, across almost every species. All were small fish. Art the end the remaining fish were very shy and hardly ate), and I had the disease confirmed by a fish vet.

That's not the only option though, you can treat with a UV Steriliser and a few months of that treatment can be enough to contain the outbreak, saving any fish who have not already been badly infected, and apparently then you can add new fish who will not catch the disease. Diana Walstad wrote an article about it here with her experiences - Mycobacteriosis in Aquarium Fish
Let me know if you need more info on the UV as I researched that quite a bit too, and bought one to help stop future outbreaks.

 

[peaches]

I will look at Walstads post. I did treat last Thursday with NT Labs Anti fluke and wormer , which is flubendazole. Straight after all the livebearers had irregular white shaped poo, and today another fish has produced some ( I thought it was all over). Everyone OK today. I'm going to do a large water change and clean one of my filters.

The NT labs treatment wasn't the first wormer I had used. I had used praziquantel last month.

I am not totally convinced it's tb...but I don't know what else it is and I am not moving anything in or out of this tank.

I have two other tanks that are OK.

 

[peaches]

Yes tell me about the UV. I didnt think they could cure it.

 

[peaches]

Looks like Walstad had success with UV. Do you have to have external filtration to run UV? I cannot bend down to maintain externals (bad back) so I run 2 internals.

 

[PARAGUAY]

You can run a UV as a unit . They typically work like an internal filter going drawing the water through sponge. Downside in a smaller tank like a internal filter they can take space up.

 

[Simon Cole]

Chemical treatments and ecosystem balance
The treatments that you have used so far have included: flubendazole (NT Labs Anti fluke and wormer), praziquantel, protozin and myxazin.
When a lot of biocides have been used in an aquarium, it is probably a bit harder to control bacterial diseases because protozoa, flagellates, ciliates, rotifers and other life forms that consume or supress pathogenic bacteria are adversely affected. When fish consume infected dead fish it is logical that they should show evidence of cysts in their digestive tracts if they contract the same infection through ingestion. A large population of shrimp and snails may well consume dead infected fish before they can be ingested by vulnerable living fish. Detritus worms and other invertebrates have a positive function in consuming dead infected tissue, and smaller organisms can even consume the pathogenic bacteria themselves. My experience indicates that bee pollen helps to maintain a healthy population of these communities. If these ecosystem communities have been destroyed with biocides then I would put a bit of clean garden topsoil into the aquarium to re-establish them.

Ultra violet
When I researched the wattage requirements of UV bulbs I felt that 25 watts or higher might be effective. I do consider using UV in treatment tanks where there is a residual potential (post treatment) for water-bourn infection and I want to create a sterile environment to aid healing, such as with external lesions. However, usually I am sterilising the tank and filter every two days and performing a complete water change, so it doesn't seem advantageous. I never use UV for active infections because in those circumstances I tend towards antibiotics or other treatments that might denature in the presence of UV light, hence it is usually superfluous or counterproductive. Even though I have this equipment for several years, I have never found it that useful. If I had treatment-resistant Ichthyophthirius multifiliis then there would be an obvious application for UV, and similarly I can think of examples of how the technology might be applied to new fish quarantine tanks, breeding systems, and to benefit species that are sensitive to alternative chemical treatments. I would feel uncomfortable using UV in an aquarium ecosystem because it could damage beneficial microbes that are mitigating the prevalence of pathogens.

Diet
I think it is transmission through consumption which is causing infection in the digestive tract. In healthy digestive tracts there is a balance of different microbes and a gut lining which protects the fish from disease. The same thing applies to gum disease in humans: if people use too much chlorhexidine digluconate mouthwash then this is known to cause significantly worse gum disease because there are not enough good microbes supressing the infectious ones. For fish, the first thing I will do is to improve the diet and replace existing food that could be the original vector of infection. I would almost go so far as to suggest that the preservatives within and quality of certain commercial foods is what creates the conditions for disease. There have also been growing number of severe outbreaks of disease in farmed salmon. Much of this is marked unfit for human consumption, but there is little guarantee that dead diseased fish called "morts" do not make their way into processed fish food, potentially causing disease incidence in aquarium fish. I have seen videos of piles of dead disease-ridden salmon removed from enclosures and stacked by the side of them. There were several high profile break-ins by animal rights activists in Scotland filming these conditions which shocked me and prompted me to reduce fish meal from my aquarium fish food as a precaution. Also, we have noticed on more than one occasion that contaminated decomposing frozen foods can cause gastric infections in fish, especially Corydoras. I don't have much to say on the matter except that those tiny pouches of frozen food that people have sold me will often smell rank, and I have observed them defrosted on arrival at local fish shops. I prefer to feed live foods. I currently give my fish about 50% worm, 30% insect, 10% vegetable and 10% processed food. I am looking for a balanced natural diet and find that the right fish food is the single best way of avoiding or mitigating disease. Worms are underrated in my opinion. You can gut load them with a highly nutritious vitamin and mineral rich diet and they will pass these biological molecules up the food chain to fish. They also have an excellent fat and protein content. To me it seems logical that the slime coat on certain worms has a very reasonable balance of natural microbes that benefits the digestive tract of fish. Furthermore, the glycoproteins that make up the slime coat on worms may have similar protective properties inside fish digestive tracts. I would look to culture Grindal worms, California Blackworms and white worms. Finely chopped small brandling earthworms Eisenia fetida are can be a good alternative if you purge them of what they have consumed, or if their diet has been soil and leaf matter as opposed to waste feedstocks.

Decontamination
There are ways to decontaminate your aquarium after the fish have been removed using potassium permanganate. Since you have already nuked a lot of beneficial fauna with the chemicals that you have used, there is no disadvantage to removing the fish and sterilising the aquarium using this chemical and there are also several advantages that I could think of over UV.

Bacterial disease in fish
So I am hinting that your fish might have a gastric bacterial infection that is being transmitted by consumption. I am not going to confirm that it is TB, mycobacterium or anything that we can label yet. When I encountered severe TB many years in the past, I observed rapid mortality, symptoms of acute septicaemia, and exploding fish that would disintegrate. In those severe cases, water-bourn or contact-transmitted infections usually show as lesions on the outside body of the fish, gill damage etc and there is not a long period of senescence. When it is a gastric bacterial infection you will often see reddened or swollen areas above the anal fin in Corydoras and it is obvious where the infection is localised. There are a wide variety of pharmaceutical antibiotics that you could try, but in order to do so, you need to follow a course of dosing and ensure that the pharmaceutical antibiotic is not released into sewerage or the environment. The protocols for using pharmaceutical antibiotics in aquariums should be quite strict. You should follow the full course duration. You should destroy the pharmaceutical antibiotics in any water that you remove from the treatment tank using potassium permanganate or a suitable alternative. You should avoid formulated fish foods because they are extensively banned and have dire environmental consequences. As has been mentioned, TB is a zoonotic disease that can kill humans. The last thing we want is a pharmaceutical antibiotic-resistant disease outbreak in your home then sweeping through God's own county. If you fancy giving pharmaceutical antibiotics a try then this is only really done in a controlled environment like a sterile treatment tank. Some fish will recover, others will not. Personally, I do not see any merits in this approach. I suspect it is not a very severe form of TB if it is this disease, and you need good certainty of the diagnosis and benefits of treatment before you proceed with pharmaceuticals. Conversely, I cannot envision a fast fix using any number of chemical antibacterial treatments. I stopped using conventional shop-bought treatments completely because they never worked and only caused excessive fish mortality, and the toxicity of many treatments stunned me; inhumane.

Antimicrobial environments can be created naturally. Indian almond leaves have a wide variety of antimicrobial compounds and have an established orthodoxy in treating sick fish. Whether they have any benefits with relation to gastric bacterial infection is anybody's guess. I would have thought you best bet is to enable the fish to recover naturally and be more proactive in quarantining sick or diseased fish. I have recovered fish from gastric bacterial disease but it takes many months and there is usually a high mortality rate to be expected. That is why many people suggest euthanasia.

 

[peaches]

Simon, thanks for this detailed response. I will deal with it in sections.
FROZEN FOOD, CORYS.
This is one point I have given a lot of thought to.
I have a range of frozen foods which I am using on other tanks to condition fish. I also grow my own daphnia, indoors in a tank, fed mostly on green water, small amounts of powdered spirulina.
I have a batch of snail food made up thus: pureed Brussels sprouts, repashy soilent green, calcium carbonate, gelatine. Cut into squares and frozen. I put this in for my applesnails (pomacea diffusa?). However, every single fish makes a beeline for this. They all had some twice a week. I was surprised the cories were on it too, didn't seem like their thing. Bristlenose love it. I havent fed it for 10 days as I started to suspect it. I had 12 cory 6 Venezuela 6 panda. The panda were quite small and with hindsight should have grown them on in their own tank...but didn't. From January I lost a cory a week, all the panda ones first. Then 4 Venezuela. 2 remain. (Relevant because of your mention of stomach bacteria?) The bristlenose are healthy, no fatalities whatsoever. These are mostly juvenile and I wanted to move these out to a separate breeding tank, but I'm loathe to move anything now during the deaths.
I have had UV a week now. Lost a platy yesterday, no external signs, but just after water change. He just died suddenly, was swimming slightly irregularly for less than 5 minutes. Then died. Fished him out, looked completely clean, no lesions, no clue whatsoever. Didn't look emaciated.
Now not sure what to feed. I have 3 other tanks. No deaths. Nothing from the death tank goes in there. Own nets, separate food.
Now don't know what to feed. I am culturing microworms for my breeding projects. Do you consider them a suitable food?

 

[peaches]

Simon...Disinfectation and decontamination.
This kind of goes against a lot of my fishkeeping principles. It's a fully planted 200L. Has 2 internal filters. The largest a juwel biofilter has been running 3 years, the smaller one U4, 5 month. Isn't decontamination pointless unless you deal with filter media? But then, you end up with no mature media. what the hell do you do with existing stock? Still quite a few fish left.

 

[peaches]

Simon, Bacterial disease in fish...acute septicaemia....lesions...Gill damage.
Not seen any of this. I don't go out to work, I have health problems, and spend a large part of my day seated next to my 200L. I see fish going down, they swim irregularly or hide. But I cannot think of one of the deaths with any marks. No red patches which may indicate septicaemia. Not seen any swollen abdomen, pop eye, protruding scales. The first panda cory I lost had a nipped fin. But unfortunately some of the other corys were part consumed before I got to them. I hadn't suspected MB then. I blamed the fact that I hadn't quarantined the cory. Now I am very quick. If any fish is swimming irregularly, I monitor them. If this occurs near bedtime that fish goes in my largest netbreeder to observe, so no predation. I have been sterilising my nets and netbreeders in Milton sterilising fluid. But apparently this isn't enough, Walstad says bleach doesn't kill it. I am now using different nets to different tanks, each has its own. Kept separate.

 

[peaches]

I do realise I cannot just watch and do nothing, but taking apart the tank...in practical terms...how?

Filters...

 

[peaches]

It could be either, sometimes it seems fish catch things after a stressful event (like moving tanks) which suppresses the immune system enough for something already living relatively inertly in the tank or in the fish to take over.

Symptoms like stringy poop and thinness imply a stomach parasite of some sort, so I would treat for worms with Esha NDX first and see how that goes. I have been recommended Esha Optima before by a fish vet to help get up fish's immune system, soi would treat with that too. I would also feed more live food if possible to help with their health.

There is also a possibility of fishTB, but it has many symptoms so it's often on a list of possible illnesses (thinness, stringy poop, dying one after another). FishTB can be caught by people putting their hands in the tank and is apparently painful, so while you are working out what is afflicting your aquarium, you shouldn't share equipment between tanks(it can spread this way), and you must not put your hand in the tank if it has any sort of cut or scratch on it, and ideally wear gloves.

The vet thing. How do you start this off? Do you take a corpse to the vet or a living fish?

 

[shangman]

Simon, Bacterial disease in fish...acute septicaemia....lesions...Gill damage.
Not seen any of this. I don't go out to work, I have health problems, and spend a large part of my day seated next to my 200L. I see fish going down, they swim irregularly or hide. But I cannot think of one of the deaths with any marks. No red patches which may indicate septicaemia. Not seen any swollen abdomen, pop eye, protruding scales. The first panda cory I lost had a nipped fin. But unfortunately some of the other corys were part consumed before I got to them. I hadn't suspected MB then. I blamed the fact that I hadn't quarantined the cory. Now I am very quick. If any fish is swimming irregularly, I monitor them. If this occurs near bedtime that fish goes in my largest netbreeder to observe, so no predation. I have been sterilising my nets and netbreeders in Milton sterilising fluid. But apparently this isn't enough, Walstad says bleach doesn't kill it. I am now using different nets to different tanks, each has its own. Kept separate.

Some of my sick fish did have lesions, red and white patches, gill damage, dropsy and popeye, but others died with no symptoms at all. It depends on the types of fish attacked I think, and how virulent the disease is. There are several types of fish TB and some are worse and faster than others. I still think there is a chance your tank doesn't have fishTB as the fish don't have all the symptoms.

Bleach does kill mycobacterium, but it needs a strong dose with a day of contact. As my fish had so many nasty symptoms and were all acting very shy and not eating food much, I decided to euthanise, destroy all organics in the tank and bleach everything thoroughly. I have the recipe for the beach cleaning in my journal.

The vet thing. How do you start this off? Do you take a corpse to the vet or a living fish?

I contacted the London Fish Vet by email. We had a phone call which cost £35 for half an hour, she didn't think it was myco but I did so I insisted on a test for it anyway which is a histopathology.

The vet didn't do the histopathology, she prepared the fish and sent them off to the lab, after I delivered the fish to her directly alive as I thought she'd do a better job of it, but there was an option that she sends me a kit to preserve the fish and then I could send directly to the lab. The vet did a scrape on the fish for free just before she euthanised them, which showed the fish had some trichodina parasites.

It cost £134 for the histopathology, sending over two small fish. It costs more of the fish are bigger. I got the results back within a week, and it confirmed fishTB via granulomas in the fish (basically tumours).

 

[peaches]

Some of my sick fish did have lesions, red and white patches, gill damage, dropsy and popeye, but others died with no symptoms at all. It depends on the types of fish attacked I think, and how virulent the disease is. There are several types of fish TB and some are worse and faster than others. I still think there is a chance your tank doesn't have fishTB as the fish don't have all the symptoms.

Bleach does kill mycobacterium, but it needs a strong dose with a day of contact. As my fish had so many nasty symptoms and were all acting very shy and not eating food much, I decided to euthanise, destroy all organics in the tank and bleach everything thoroughly. I have the recipe for the beach cleaning in my journal.


I contacted the London Fish Vet by email. We had a phone call which cost £35 for half an hour, she didn't think it was myco but I did so I insisted on a test for it anyway which is a histopathology.

The vet didn't do the histopathology, she prepared the fish and sent them off to the lab, after I delivered the fish to her directly alive as I thought she'd do a better job of it, but there was an option that she sends me a kit to preserve the fish and then I could send directly to the lab. The vet did a scrape on the fish for free just before she euthanised them, which showed the fish had some trichodina parasites.

It cost £134 for the histopathology, sending over two small fish. It costs more of the fish are bigger. I got the results back within a week, and it confirmed fishTB via granulomas in the fish (basically tumours).

Thankyou. I have thought of asking my local vet who cares for our dog, as they might do fish (I know the family of one of the vets and they keep fish). I wish I had kept yesterdays corpse as it was literally unmarked and in really good condition. Its getting hard sitting looking at the fish thinking which is next.

 

[shangman]

Thankyou. I have thought of asking my local vet who cares for our dog, as they might do fish (I know the family of one of the vets and they keep fish). I wish I had kept yesterdays corpse as it was literally unmarked and in really good condition. Its getting hard sitting looking at the fish thinking which is next.

It's worth trying, maybe they can send the fish off to the lab, the vet did a scrape but not the histopathology themselves. Don't beat yourself up about the dead fish yesterday, for the histopathology the fish needs to be very freshly dead and then preserved in formalin immediately so it is best to do it with a just euthanised fish. Personally I waited until a fish had symptoms and then sent them off for best results.

 

[Simon Cole]

@peaches - I am so sorry that I missed your post. Please use the @ symbol to get me.
I would love to try and help you and at least give my opinion.

I have had the exact same issue a few years ago, which started with newly-purchased Panda corydoras (Corydoras panda) and spread to other fish. I put it down as Aeromonas, and in my case it was probably triggered by contaminated frozen bloodworm and initiated due to the fact that the fish had a weak immune system. I would place a bet that the treatments used in aquarium fish farming either damage the microbial balance inside this particular species or work in such a way as to make them more vulnerable to digestive tract infections. My diary reveals that I did use isostatically-balanced aquarium salt (even though they are thought to prefer lower salt concentrations in the wild) and this was fine. I tried Interpet Anti Fungus and Fin Rot 100ml (number 8) which contains phenoxyethanol first (I was quite naïve back then 🙄) in a sterile, highly-aerated, quarantine tank, also feeding a decent flake food: the results were catastrophic. I cannot advise people enough to avoid phenoxyethanol. I then tried a parasite and worm treatment and saw no changes, before finally trying EHSA 2000. I do not think that these treatments did very much if anything at all, but EHSA 2000 is well respected and may have helped, but it's not ideal for shrimp and snails due to the copper content. Over a few more weeks the fish gradually recovered and the disease disappeared for good. If I had lots of fish then I would opt for doxycycline in a controlled treatment tank because it works well for me and there are studies supporting my findings. For your situation, I might not bother to set up a treatment tank. You could look into other commercially-available treatments if you feel that it is likely to be Aeromonas; I think there are a few around and they should be far cheaper, possibly more effective and readily available.

I am culturing microworms for my breeding projects. Do you consider them a suitable food?

Yes - primarily I use Grindal worms for recovery after I have completed the dosed treatment.

Isn't decontamination pointless unless you deal with filter media? But then, you end up with no mature media. what the hell do you do with existing stock?

Existing stock go into a bucket and have to put up with it for a day. The water gets changed before they are put back. If you go for that option, I support the dosage concentrations of potassium permanganate recommended here. I do not think it is that necessary because I think of Aeromonas as an opportunistic infection, but if you feel that it is too abundant to avoid disease reoccurrence, then you could either do the tank and ignore the filter, or do both. I cannot say whether it is necessary because I do not know, but it is something I would consider for infections like columnaris Flavobacterium columnare (when I have uncertainty and am planning on reintroducing fish from their treatment tank and back into the previous aquarium).

health problems

Some aeromonas is zoonotic and can be transmitted to humans. Wash hands with soap and wear gloves if you have cuts. It is usually treatable in humans, but I wanted to mention just in case so that you are aware.

taking apart the tank...in practical terms...how?

That might not be necessary if the abundance of the pathogen in the aquarium lowers sufficiently to reduce disease, or it disappears. Potassium permanganate as a decontaminant is non-destructive to plants and hardscape, but it may stain rocks for a few days if you have one that reacts. It may affect microbial communities, but plants do most of the work (Darrel's "headline news") mediating nutrient levels and bio-adsorption of other organic molecules, so you might be able to get away with this. I wouldn't bother personally... but then again, would I... if I knew it was aeronomas and could spread elsewhere... given how much of a problem it now is??? ...not sure.

I still think there is a chance your tank doesn't have fishTB as the fish don't have all the symptoms.

Those are my thoughts too.

It cost £134 for the histopathology

Balanced against the costs of treatment, you could probably order and get delivered: a new quarantine tank, pump, air stone, tubing, new food and pharmaceutical medication for that price, and still have enough for a booze-up down the local 🍺.