[FONT=Comic Sans MS, cursive]Having recently set up an aquarium again after a lapse of several years, I have been unfortunate enough to acquire a fairy severe case of Fish Tuberculosis in the tank. This triggered me to write down here exactly what I do know of the disease and what the various books I possess say about it. There seems to be little on the www other than anecdotal evidence. [/FONT]
[FONT=Comic Sans MS, cursive]I would stress that I am no expert: this is a compilation of information from various sources. [/FONT]
[FONT=Comic Sans MS, cursive]Fish tuberculosis is not the same as the human disease of the same name. However it is possibly the most common disease amongst aquaria fish. It is a high probability than anyone who has kept a range of tropical fish for any length of time will have experienced it. However - it is also quite unlikely that they will have realised this, for the disease is usually not virulent, is not usually highly contagious and does not have sudden and drastic effects. [/FONT]
[FONT=Comic Sans MS, cursive]However: in certain cases the disease can occur epidemically and then great losses will occur. But more usually an infected fish may die years after it initially gets infected. Often the fish shows no external symptoms and the death is usually one of those unexplained death that all aquarists have experienced amongst their pets. [/FONT]
[FONT=Comic Sans MS, cursive]Fish TB, quite apart from being about the most common disease and about the hardest to diagnose, is also about the hardest to cure. [/FONT]
[FONT=Comic Sans MS, cursive]This page is written in part from my own experience and in part from the books I have. I have quoted chunks and information from [/FONT]
[FONT=Comic Sans MS, cursive]Diseases of Fishes[/FONT][FONT=Comic Sans MS, cursive], by C van Duijn Jr, published by Iliffe Books Ltd. in 1956. The book contains a lot of highly technical information including photographs of specimens and several photomicrographs of the tubercles. Much of the book's information is highly technical and has not been paraphrased here. [/FONT]
[FONT=Comic Sans MS, cursive]Another book which is informative is 'Aquarium Care' by Gunther Sterba, published in Britain in 1967 by Studio Vista Ltd. [/FONT]
[FONT=Comic Sans MS, cursive]These are old books and hopefully more up-to-date information exists. Nevertheless I hope the information here proves useful to other aquarists. If I am in error on anything, or you have information to add to what is here, please contact me. [/FONT]
[FONT=Comic Sans MS, cursive]What is fish TB?[/FONT]
[FONT=Comic Sans MS, cursive]Fish Tuberculosis is a bacterial disease. Sterba says that it is very common and he claims that 25-30 per cent of aquarium fish may be infected. The disease, says Sterba, is most prevalent in overstocked community tanks. This he says is because: [/FONT]
- [FONT=Comic Sans MS, cursive]The majority of infected fish show no symptoms. [/FONT]
- [FONT=Comic Sans MS, cursive]Hitherto (1967) every method of treatment has proved unsuccessful. [/FONT]
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Several different bacteria may cause it, all are members of the Mycobacterium genus: [/FONT]
- [FONT=Comic Sans MS, cursive]Mycobacterium piscium [/FONT]
- [FONT=Comic Sans MS, cursive]Mycobacterium platypoecilis [/FONT]
- [FONT=Comic Sans MS, cursive]Mycobacterium anabanti [/FONT]
- [FONT=Comic Sans MS, cursive]Mycobacterium fortuitum [/FONT]
- [FONT=Comic Sans MS, cursive]Mycobacterium salmoniphilum [/FONT]
- [FONT=Comic Sans MS, cursive]Mycobacterium marinum [/FONT]
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The above list is not exhaustive! If you search the www, you will find a lot about mycobacterium marinum - which appears to be the most studied cause, but probably not the commonest. Sea fish are commercially more valuable than pet fish and the fish-farm industry can support a lot of research into diseases. [/FONT]
[FONT=Comic Sans MS, cursive]Clearly you need to be a bacteriologist to properly study the infection! But the bacteria that cause fish TB only cause TB in cold-blooded animals. Human tubercle bacteria are not pathogenic for fishes. [/FONT]
[FONT=Comic Sans MS, cursive]What are the symptoms?[/FONT]
[FONT=Comic Sans MS, cursive]Exactly what symptoms appear depend on the affected species (and presumably on the bacterium). In the early stages of the disease, no symptoms whatsoever are apparent and, even in the later stages, often the only way to diagnose the disease is by dissection and microscopic examination of the internal organs (especially the intestines, liver and kidneys), where tuberculous cysts may be found. [/FONT]
[FONT=Comic Sans MS, cursive]All the bacteria of the genus Myobacterium are acid-alcohol fast, this is to say that the bacteria, after having been stained with a phenol solution of fuchsine, retain this stain on treatment with a dilute mineral acid and ethanol. Clearly such tests are not for the usual amateur aquarist! [/FONT]
[FONT=Comic Sans MS, cursive]The tubercles are formed initially in the internal organs and appear as small, dirty grey knots, often containing necrotic tissue of blackish colour. These tubercles may have very different sizes and, especially in small fish, may only be found with the aid of a microscope. Normal tissue is pushed aside by the growing tubercles and if these tubercles grow near or into a blood vessel the circulation can be hindered and sometimes bleeding can occur. [/FONT]
[FONT=Comic Sans MS, cursive]The infection may also spread to the skeleton and then deformities may result, such as crooked spine, deformed cheeks and damaged fin-rays. [/FONT]
[FONT=Comic Sans MS, cursive]Clearly such deformities weaken the fish which will die as soon as the damage gets too severe. However the more delicate species may die an an early stage, before any visible symptoms appear. The more robust specimens, particularly if their general health is good, can withstand the disease much longer and will only die when some of the visible symptoms occur. [/FONT]
[FONT=Comic Sans MS, cursive]There is a huge range of visible symptoms, most of which are not specifically diagnostic of fish TB as they can also occur with other diseases. So there is an extremely good chance of fish TB being incorrectly diagnosed as something else entirely - which would indicate that fish TB is likely to be far commoner than most books (and fish dealers!) would admit. Although Sterba's book was written in the 60s, maybe his pessimistic-seeming "25-30% of fish are infected" is not as pessimistic as it might seem! [/FONT]
[FONT=Comic Sans MS, cursive]Symptoms can include: [/FONT]
- [FONT=Comic Sans MS, cursive]Loss of appetite [/FONT]
- [FONT=Comic Sans MS, cursive]Progressive thinness [/FONT]
- [FONT=Comic Sans MS, cursive]Sluggish movement [/FONT]
- [FONT=Comic Sans MS, cursive]Folded fins [/FONT]
- [FONT=Comic Sans MS, cursive]Eye protrusion [/FONT]
- [FONT=Comic Sans MS, cursive]Dark coloration and granular appearance of the cornea (this is the first sign in Angelfish). [/FONT]
- [FONT=Comic Sans MS, cursive]Skeletal deformity [/FONT]
- [FONT=Comic Sans MS, cursive]Hanging at the surface [/FONT]
- [FONT=Comic Sans MS, cursive]Skin defects, including blood spots and open wounds that may ulcerate [/FONT]
- [FONT=Comic Sans MS, cursive]Black spots, or overall dark coloration (in Cichlids particularly). [/FONT]
- [FONT=Comic Sans MS, cursive]Fin rot, characterised by the outer rays falling out. [/FONT]
- [FONT=Comic Sans MS, cursive]Scales loosening and falling out [/FONT]
- [FONT=Comic Sans MS, cursive]General swelling and scale protrusion (as in Dropsy) [/FONT]
[FONT=Comic Sans MS, cursive]How are fish infected?[/FONT]
[FONT=Comic Sans MS, cursive]Sterba says that infection may be by every conceivable route. Bacilli may be in the faeces, scraps of skin or burst abscesses and can be ingested by healthy fish. If infected fish die and are eaten by others (as we have all seen, on occasion, in a poorly attended fish retailer's stock tanks) then an overwhelming infection may result. [/FONT]
[FONT=Comic Sans MS, cursive]What fish are susceptible?[/FONT]
- [FONT=Comic Sans MS, cursive]Cyprinids and cyprinodonts in general, including [/FONT]
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Cyprinids. [/FONT]
- [FONT=Comic Sans MS, cursive]Giant Danio - [/FONT][FONT=Comic Sans MS, cursive]Danio malabaricus[/FONT]
- [FONT=Comic Sans MS, cursive]Guppies - [/FONT][FONT=Comic Sans MS, cursive]lebistes reticulatus[/FONT]
- [FONT=Comic Sans MS, cursive]Golden Carp - [/FONT][FONT=Comic Sans MS, cursive]Cyprinus carpio[/FONT]
- [FONT=Comic Sans MS, cursive]Goldfish - [/FONT][FONT=Comic Sans MS, cursive]carassius autatus[/FONT][FONT=Comic Sans MS, cursive] [/FONT]
- [FONT=Comic Sans MS, cursive]Pike-perch - [/FONT][FONT=Comic Sans MS, cursive]Lucioperca sandra[/FONT][FONT=Comic Sans MS, cursive] [/FONT]
- [FONT=Comic Sans MS, cursive]White cloud mountain minnow - [/FONT][FONT=Comic Sans MS, cursive]Tanichthys albonubes[/FONT][FONT=Comic Sans MS, cursive]
Cyprinodonts [/FONT]
- [FONT=Comic Sans MS, cursive]Sword-tails - [/FONT][FONT=Comic Sans MS, cursive]Xiphophorus helleri[/FONT][FONT=Comic Sans MS, cursive] [/FONT]
- [FONT=Comic Sans MS, cursive]Tetras in general, including [/FONT]
- [FONT=Comic Sans MS, cursive]Black Widows - [/FONT][FONT=Comic Sans MS, cursive]Gymnocorymbus ternetzi[/FONT]
- [FONT=Comic Sans MS, cursive]Neon Tetra - [/FONT][FONT=Comic Sans MS, cursive]Hyphessobrycon innesi[/FONT]
- [FONT=Comic Sans MS, cursive]Anabantids in general, including [/FONT]
- [FONT=Comic Sans MS, cursive]Mosaic Gourami - [/FONT][FONT=Comic Sans MS, cursive]trichogaster leeri[/FONT]
- [FONT=Comic Sans MS, cursive]Paradise Fish - [/FONT][FONT=Comic Sans MS, cursive]Macropodus opercularus[/FONT]
- [FONT=Comic Sans MS, cursive]Honey Gourami - [/FONT][FONT=Comic Sans MS, cursive]Colisa sota[/FONT][FONT=Comic Sans MS, cursive] [/FONT]
- [FONT=Comic Sans MS, cursive]Dwarf Gourami - [/FONT][FONT=Comic Sans MS, cursive]Colisa lalia[/FONT]
- [FONT=Comic Sans MS, cursive]Cichlids, including: [/FONT]
- [FONT=Comic Sans MS, cursive]Fire-Mouth Cichlid - [/FONT][FONT=Comic Sans MS, cursive]Cichlasoma meeki[/FONT]
- [FONT=Comic Sans MS, cursive]Ramirez' Dwarf Cichlid - [/FONT][FONT=Comic Sans MS, cursive]Apistograma ramirezi[/FONT]
- [FONT=Comic Sans MS, cursive]Egyptian Mouth-Brooder - [/FONT][FONT=Comic Sans MS, cursive]Haplochromis multicolor[/FONT]
- [FONT=Comic Sans MS, cursive]Angel Fish - [/FONT][FONT=Comic Sans MS, cursive]Pterophyllum sp[/FONT]
- [FONT=Comic Sans MS, cursive]Various other species: [/FONT]
- [FONT=Comic Sans MS, cursive]European Catfish - [/FONT][FONT=Comic Sans MS, cursive]siluris glanis[/FONT][FONT=Comic Sans MS, cursive] [/FONT]
[FONT=Comic Sans MS, cursive]Clearly - this is not an exhaustive list and a list if immune fish is not possible, but it should give an idea of the problems you may face! It is compiled partly from my own experiences and partly from the books I possess. The sheer variety of fishes which can succumb surprised me as I was expecting Cyprinids, Tetras and Anabantids - all 3 genera appear particularly sensitive. [/FONT]
[FONT=Comic Sans MS, cursive]I suppose that, looking at the range of names of the causal bacteria, one might get a clue as to the species of fish involved. However a single outbreak will presumably be one bacterium species only so might be expected not to affect all fish. Van Duijn gives significant detail on the various bacteria and the fish species they infect. [/FONT]
[FONT=Comic Sans MS, cursive]Marine fishes are not immune, neither are frogs, caymans, tortoises and other cold-blooded animals, but there are different strains of bacteria involved. [/FONT]
[FONT=Comic Sans MS, cursive]Logic would indicate that carnivorous fishes are likely to be somewhat immune - after all they are going to eat in the wild, infected fish and would be the first to succumb therefore, so one could expect natural immunity. [/FONT]
[FONT=Comic Sans MS, cursive]Cures and treatment[/FONT]
[FONT=Comic Sans MS, cursive]Effectively, there is no sensible cure. The only way to cure the infected aquarium is to immediately remove infected fish as soon as they show any symptoms. Ideally all other susceptible fish should also be removed. [/FONT]
[FONT=Comic Sans MS, cursive]Van Duijn cites cases where treatment of the open wounds with penicillin ointment have effected a cure. As the disease is bacterial, antibiotics should work, but in general these are only available on veterinary prescription and injection of infected fish may be required, so such cures are hardly useful,to the average aquarium keeper. [/FONT]
[FONT=Comic Sans MS, cursive]Sterba says that the spread of the disease can be hindered by: [/FONT]
- [FONT=Comic Sans MS, cursive]Good husbandry and a varied diet can prevent acute symptoms, even in infected fish. [/FONT]
- [FONT=Comic Sans MS, cursive]All fish with external signs must be removed immediately and killed: never use them for breeding. [/FONT]
- [FONT=Comic Sans MS, cursive]Fish which have shared a tank with an infected one should not be given away or sold but should be isolated and carefully looked after. [/FONT]
- [FONT=Comic Sans MS, cursive]In breeding tanks, diseased stocks must be destroyed and the tank disinfected with 1:1000 potassium permanganate solution [/FONT]
[FONT=Comic Sans MS, cursive]Can Fish TB affect humans?[/FONT]
[FONT=Comic Sans MS, cursive]Most of the info you will find on the www seems to indicate that fish TB can infect humans. However - most of this info refers to the marine disease, caused by Myobacterium marinum. [/FONT]
[FONT=Comic Sans MS, cursive]In Freshwater fish, the disease has different causal bacteria and both of the books I have indicate that these are not dangerous to humans and that these bacteria are generally only dangerous in cold-blooded organisms, so trouble in humans would seem to be less likely with the freshwater varieties. [/FONT]
[FONT=Comic Sans MS, cursive]However - there are lots of different organisms that cause fish t.b. and I have heard reports of some people being infected by freshwater varieties, so it may be rare but not, it seems, impossible! [/FONT]
[FONT=Comic Sans MS, cursive]It seems that human infection comes via cuts and skin abrasions. [/FONT]
[FONT=Comic Sans MS, cursive]Tropical fish-keeping is so common, and fish TB so common, that surely if there were high danger, freshwater fish TB would be much better investigated and not the cause of mystery deaths that it quite clearly is! However human affairs don't always follow that logic! [/FONT]
[FONT=Comic Sans MS, cursive]How can I avoid such infections in my fish?[/FONT]
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Buy fish only from reputable dealers. Carefully inspect all the tanks of the dealers - if there are any significant quantity dead or sick looking fish, avoid the dealer entirely (unless the sick fish are clearly quarantined and being looked after). A good dealer will remove any sick or dead specimens immediately. If left in the show tank, it's a clear indication of bad husbandry, for dead bodies get eaten by other inhabitants, and this is a sure way of spreading infection. I recently (28th March 2003) visited one fish dealer and saw several of their 90 odd tanks where there were dead fish. Some corpses were fresh: others had decayed/been eaten and some were simply skeletons. Several tanks had 4 or five such corpses. Clearly such a dealer should be avoided. [/FONT]
[FONT=Comic Sans MS, cursive]I did engage this dealer in a long discussion about their tanks and TB and he said that he hadn't cleaned the tanks that morning (how many days does it take a dead fish to decompose to become a mere skeleton?) and that you had to multiply the normal fish death-rate by 90 as he has that number of tanks. Are his [/FONT]
[FONT=Comic Sans MS, cursive]young[/FONT][FONT=Comic Sans MS, cursive] fish in such a poor state that he expects [/FONT]
[FONT=Comic Sans MS, cursive]any[/FONT][FONT=Comic Sans MS, cursive] significant death rate? If so - he should change his supplier! [/FONT]
[FONT=Comic Sans MS, cursive]Talk to the dealer about diseases, particularly TB, and about their suppliers. Is the dealer interested and caring and aware of the problems? You have in this page a lot of background information. If your dealer is interested - you should now be able to teach him some things. [/FONT]
[FONT=Comic Sans MS, cursive]Unfortunately quarantining new fish is likely to be useless: infected fish may die many months after first being infected, so a quarantine of a few weeks will show nothing. [/FONT]
[FONT=Comic Sans MS, cursive]Can I introduce TB with live food.[/FONT]
[FONT=Comic Sans MS, cursive]Clearly, lacking any statistics, the obvious safe answer has to be 'yes'. However, my feeling is that it is not at all likely. [/FONT]
[FONT=Comic Sans MS, cursive]Consider the following: [/FONT]
- [FONT=Comic Sans MS, cursive]A pond full of daphnia is not likely to be populated with fish. Daphnia and fish mix well, but the fish always win! [/FONT]
- [FONT=Comic Sans MS, cursive]There are very many TB bacteria: types which infect crustacea (specifically daphnia) are unlikely to survive in fish. Daphnia is, after all, a natural fish food and evolution will have sorted out any tendency for dangerous organisms to be transmitted via the food chain [/FONT]
- [FONT=Comic Sans MS, cursive]Natural waters are far less densely populated than any fish dealer or aquarists tank, so conditions for spreading the disease are less favourable. [/FONT]
- [FONT=Comic Sans MS, cursive]TB bacteria will grow faster in a tropical tank at 25° than in native waters which are usually much colder. [/FONT]
- [FONT=Comic Sans MS, cursive]Fish fed on live food are likely to be in peak condition, so will be generally more resistant to disease. [/FONT]
- [FONT=Comic Sans MS, cursive]A healthy aquarium, like any closed ecosystem, must have lots of different organisms in balance for best health. Introducing live food from a local pond will introduce new bacteria, animals, worms etc which will all assist the biodiversity of your tank (as well as adding to its interest). Yes, try and use pond water from a source that does not contain fish: if there are no fish, there is virtually no chance that you will introduce disease or parasites. [/FONT]
[FONT=Comic Sans MS, cursive]But learn about pond life: if you, for instance, add dragon-fly larvae to your tank - they are carnivorous and will catch and eat very small fish. But if you have big fish - they are simply more and tasty fish-food. There are many small pond animals like this which can damage small fish but will be good food for larger fish! [/FONT]
[FONT=Comic Sans MS, cursive]Can I introduce TB with dried food.[/FONT]
[FONT=Comic Sans MS, cursive]I do not know the answer to this. However, look at the ingredients on a typical flake food: it contains all sorts of ingredients - many of which are fish-derived. If a sick fish did get used as an ingredient - well, bacteria are known to ne able to survive al sorts of harsh conditions and I dare say that processing as fish food might not kill them all. [/FONT]
[FONT=Comic Sans MS, cursive]Manufactured fish foods are after all wide-range: they are designed to feed a wide variety of fish, from vegetarian ones to carnivores. Not all fish eat the same diet naturally and food should ideally be matched to what the particular fish, in nature, would normally eat. [/FONT]
[FONT=Comic Sans MS, cursive]So transmission via flake food would, I anticipate, be a subject worth study! But it is far less likely than is infection from a fish shop: as we know TB can stay dormant in a fish for a long time. [/FONT]
Here are two pic's of his injury. I treated the tank with stress coat, is there anything else I can do?? Will he be ok? Anything I need to add to the tank?
