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New treatment for "malawi bloat" may help others

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Hi I have recently trialed a non-traditional treatment for a severe case of what is normally called "Malawi Bloat". I was asked to assist with the treatment due to the fish affected being of significant value to the owner. I am NOT a Veterinarian.

The fish in question are a Malawi Mbuna species. Fish stopped eating, lost colour and some displayed rapid gill movement. Out of approximately 50 fish in the tank (all the same species) a handful showed the typical "Malawi Bloat" symptom.

I think the point really needs to be made here that "Malawi Bloat" "Bloat" and "Dropsy" are in -themselves NOT diseases. They are merely symptoms of disease. The term "DROPSY" refers to the accumulation of fluids in the tissues (some say abdomen as well). The accumulation of fluid leads the fish to display the "BLOAT" symptoms. Normally in "Malawi Bloat" the scales do not protrude until the very last stage (if at all). (In this case they did SLIGHTLY in a post-mortem examination).

I want to make the clear distinction at this stage between constipation and the more serious types of bloat.

Constipation in Malawi Africans is common and often caused by inferior diet or change of diet. The long intestinal tracts of mbuna species lends them particularly susceptible to food remaining in their digestive system and causing bloating. Constipation can lead to what is known as "Malawi Bloat" but constipation in itself is NOT the same thing and I think this leads to a lot of confusion. A high fiber green diet and the use of Epsom salts (Magnesium sulfate) is the treatment for constipation.

I am now of the firm belief that the "Malawi Bloat" commonly referred to as a disease - is not only not an actual disease - but is also not a Cichlid specific disease symptom. I believe that "Dropsy" and "Malawi Bloat" whilst both being SYMPTOMS of disease may be effectively treated the same way.

As we know Metronidazole is used to treat "Malawi Bloat". Normally Within 24-48 hours fish showing "Malawi Bloat" will begin to die - within a few days a wipe-out often occurs.

Metronidazole is used in humans and animals to treat bacterial infections in the stomach and internal organs. It attacks anaerobic bacteria so is particularly useful in treating bacterial infections in the stomach and intestines. That is why it is used for "Malawi Bloat". ( It also has anti-protozoan uses - such as in the treatment of Trich. and Gardia.)

Metronidazole is normally used in conjunction with Epsom Salts. Epsom salts can serve as a laxative so is a valuable aid in constipation. (I have recently been informed it also helps draw out moisture so may aid in the accumulation of body fluids. I am unable to independently verify this.)

So back to the Cichlids in question - a dissection was carried out on one of the first couple of fish that died. This showed an extremely swollen stomach and a body filled with a gelatinous substance hence the bloating. Poor water conditions was identified as the cause of disease as the aeration from both filters (sponge filters) had slowed considerably due to a separate issue. Overfeeding exacerbated the problem - there was uneaten food noted in the tank although that was largely from the fishes reduced appetite at the last feeding. A large amount of fish waste was in the substrate. Water changes were previously performed fortnightly (the most recent a few days prior) and the fish had been owned for a long time and had always been healthy. No new additions to the tank had been made.

I added an airstone for vigorous aeration of the tank . I started the Metronidazole treatment approximately 12 hours after the first symptoms were noted. I treated at the dose prescribed previously: 200mg tablets 5 tablets per 200L per day (up to 10 days) with 25% water change daily. (I did not follow these water change recommendations - see below).

I added salt (small handful) and Epsom salts (Magnesium sulfate). Initially I added a very small dose of Epsom salts - a few teaspoons; but following advice about the potential for magnesium sulfate to draw the fluid back out of the body I increased the dose. {This sounds contradictory to me I must say as this would appear to have the opposite effect of a laxative by I'll digress to someone more knowledgeable on the matter}. Fish were not fed following standard treatment protocol. A large water change had been carried out a few days before the signs of disease. I did a further large water change before treatment to remove the uneaten food and sediment. I performed another large water change after 24 hours. I then did not change the water for 48 hours when I performed another large change. I am not an advocate of small water changes in this situation.

Due to the valuable nature of the fish before commencement of treatment I pulled out what I regarded to be the best females and a couple of males into a separate container - a 40L esky. A fully cycled sponge filter from an unrelated tank was added to the esky. Both lots of fish were treated the same way. Fish transferred to the esky had no noticeable signs of bloat. After 24 hours the fish in the main tank had deteriorated. Likewise the fish in the esky - "bloat" was evident. The number of fish showing bloat had increased. I felt (like I have whenever I've seen Metronidazole used to treat this kind of issue previously) that the fish were not responding to treatment. I observed approximately 6 fish that looked badly effected (near death) in the main tank and in addition as one or two in the esky. In the main tank the vast majority of the remainder of the fish were showing symptoms of varying degrees.

Over the next 24 hours a couple more fish died. The condition of the fish in the main tank deteriorated to the point virtually all fish were showing severe symptoms. I removed a few fish from the main tank I knew had no chance of surviving. Firmly believing that the underlying disease is contagious I did not want to leave these fish in the tank to die.

At this point I decided to have a good think about the situation and try and separate fact from assumption. The facts I had were as follows:

* Fish are not responding to treatment

* Treatment requires antibiotic to reach the stomach

* Fish were not being fed so the digestive systems were not processing food

*The above meant (in my opinion) the treatment was not reaching the stomach

*Gram negative bacteria are a known cause of traditional "Dropsy" symptoms.

*Tetracycline is highly effective at treating fish with gram negative bacterial infections

With this in mind (and not wanting to cease the use of the Metronidazole mid treatment) I decided to commence treatment of Tetracycline (Dose rate: 375mg tablets 10 tablets per 200L - initially I used slightly under that dose) combined with the Metronidazole in the main tank - and continue with the existing treatment (no Tetracycline.) in the esky. I further made the highly controversial decision to feed the fish in the main tank a small amount of food once a day. The fish in the esky were fed every 2nd day and feeding started one day later.

Almost instantly upon adding the Tetracycline the fish in the main tank appeared to take a rapid deterioration. All lost colour - honestly I expected an entire wipe out based on initial results. I tossed the idea of doing a full water change but resisted. By the next morning the fish in the main tank look to be vastly improved. The fish in the esky not so - to the contrary there was a very sick fish. I maintained the 'control' in the esky with using Metronidazole as the treatment. I continued using Metronidazole daily. After another day I did a large water change on the tanks. I re-treated the main tank with Tetracycline and Metronidazole. I reduced substantially the Epsom salts to 1 teaspoon per 40L. I added a similar to slightly smaller amount of salt than previously. Noting a fish had died in the esky I commenced treatment with Tetracycline in the 'control' esky. (I know the esky isn't a true 'control' I'm just using the term here for simplicity.)

No fish have been lost in the few days no since treatment of the Tetracycline commenced.

In the main tank there is no bloating and overall the fish look good. In the esky the fish are still showing some signs of bloating but not as severe as prior to the Tetracycline being used.

I will keep this updated and will continue edit it as no doubt I've left things out. Bottom line though is that in THIS case of what would be commonly called textbook "Malawi Bloat" - the traditional treatment did not work (as it rarely does). The Tetracycline not only worked but led to a drastic turn around in the health of the fish. Upon commencing treatment with the Tetracycline the fish were in a very poor state and a full wipe out looked very likely.

Future trials need to be made using not only these treatments together but using Tetracycline as a standalone antibiotic. If these results are replicated this could be a revolution in the treatment of these symptoms in Cichlids..

EDITED 22/11/15:

The owner lost 10 fish total. Fish are now in excellent health, active and eating normally. The above treatment in this case was extremely successful. Hope this helps others. Cheers

Edited by none
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Misuse of antibiotics in fish frequently causes internal organ failure several months later. This also causes bloat like symptoms and the typical "mush" when dissected. It's possible the tank & filter cleanup was catalyst for improvement. Are you treating the fish separate or treating in their tank?

A good general read for antibiotic use is http://www.wetwebmedia.com/ca/volume_6/volume_6_2/mycobactera.htm

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Misuse of antibiotics in fish frequently causes internal organ failure several months later. This also causes bloat like symptoms and the typical "mush" when dissected. It's possible the tank & filter cleanup was catalyst for improvement. Are you treating the fish separate or treating in their tank?

A good general read for antibiotic use is http://www.wetwebmedia.com/ca/volume_6/volume_6_2/mycobactera.htm

Hi the fish in question have never previously been treated with antibiotics nor any other treatment other than past use of Formalin / Malachite Green and salt. Tank was cleaned before treatment was commenced. It was more the lack of oxygen that I consider to be the primary issue rather than polluted water in itself. The low oxygen environment would have been favourable for the anaerobic bacteria. The uneaten food in the tank was a result of a single feeding, was still 'fresh' and was not major. The reason for the uneaten food was the ill-health of the fish (unknown at that time). They were not fed more than usual. There was a large amount of 'fresh' fish waste on the bottom partially as a result of the filter situation. The tank had been cleaned three days prior to the symptoms and fortnightly before that. Gravel clean had not been done. The filters did not require cleaning (as they'd be cleaned three days prior) just the flow of air improved. This was all done prior to commencement. The 'control' fish in the esky (not a true 'control' I know but you know what I mean) were housed in a 'new environment' albeit with a fully cycled filter. The fish moved to this tank were selected as being the healthiest and the best yet the health of these fish rapidly deteriorated until TC was used. As such I don't see the cleanup being the catalyst although it was essential. The catalyst without a doubt was the TC. As its stands no fish have been lost in 3 days. The fish now look in excellent health. Treatment is continuing. The part that is truly amazing is fish that were bloated up have returned to normal. I have never previously seen these symptoms treated where a vast majority of fish were effected yet responded to treatment to the point where the bloating is gone. As is stands only 9 fish were lost total when a total or majority wipeout appeared imminent.

I know this is only one example but to me it raises the real possibility of a successful treatment being available that could potentially save thousands of fish. The results need to be replicated. Trials need to be carried out isolating all treatments including the salt and then combining the treatments to determine if TC alone or in conjunction with MD or Magnesium sulfate or salt is the most effective. If anyone has fish with bloat they are looking to cull I would be interested in potentially obtaining those fish and doing further trials with them. Of course if a university lab wants to come on board than brilliant! Cheers

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Hi None,

Usually a bacterial colony is cultured to determine if gram positive or gram negative antibiotics (and which type) is the best remedy. Although tetracycline can be used for both situations, the widespread use in such fashion is why tetracycline is so ineffective these days. Even the newer derivatives - Chlortetracycline, oxytetracycline doxy, etc are not as effective. As you have mentioned, "bloat" is a catch phrase so the cause (and cure) for one situation may not work for another. Also since it is so insoluble in water, you need fairly high doses unless you inject or administer orally.

However my initial post was to let you know that your medications may still cause bloat in several months time. Often people aren't aware of the connection several months apart. Hopefully not though. Hopefully your fish are fixed.

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Thanks [MENTION=470]aquaholic99[/MENTION]. In this particular case there wasn't the time nor availablilty to grow a culture so a punt was taken. So far the fish all look good although he did advise he lost one more fish. I'll do another dissection in a week or so and see how the stomach etc looks. Cheers

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