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Sometimes, even with the best care and attention that we can lavish upon them, our fishes will be struck by occasional diseases. Diseases such as White Spot, which, fortunately, is easy to treat with proprietary off-the-shelf preparations, Fin Rot, and a host of other maladies. Given the number of micro-organisms that have evolved to attack fishes (the species count runs into several thousand), it's a tribute to the immune system of fishes that they are not constantly plagued with pathogens, but every now and again, some of those organisms temporarily gain the upper hand. A sudden ammonia spike in the aquarium weakening our fishes can be all it takes to spark a rampant epidemic.

However, there are some diseases in fishes that require more specialised treatment. Fortunately, these tend to be rarer in occurrence than the diseases susceptible to proprietary medication, but, occur they do now and again. And, here in the UK, one question that crops up often centres upon why it is so difficult to obtain antibiotics to treat fishes.

Lance Jepson, the resident veterinary surgeon columnnist inToday's Fishkeeper, answered this in an article in one of my back numbers. The principal reason here in the UK is legislation. Two Acts of Parliament apply to the dispensing of antibiotics by veterinary surgeons, these being the Veterinary Surgeons Act 1966, and the Medicines Act 1968.

First, the Verterinary Surgeons Act. This makes it illegal in the UK for anyone who is not a qualified veterinary surgeon, and a member of the Royal College of Veterinary Surgeons (hence the initials 'MRCVS' after a vet's name) to diagnose and treat disease in mammals, birds, reptiles and amphibians. Crucially, however, this does not include fishes. Hence the appearance in the UK of non-veterinary disease consultancies for aquarists, several of whom provide a useful and good-quality service, if somewhat expensive.

Second, the Medicines Act. This enforces a legal requirement upon a veterinary surgeon to prescribe medicines only if the animals in question are, in the terms of the Act, 'under his care'. This statement is, as Jepson says, somewhat woolly, but the Royal College of Veterinary Surgeons lays down much more precise guidelines for the meaning of this statement, including the requirement for the vet to examine the animal in question, be given legal responibility by the owner to treat the animal, and to maintain clinical records for the animal. Among the RCVS proclamations that must be adhered to is this:

"Diagnosis for the purpose of prescription should be based upon professional judgement following clinical examination and/or post mortem findings supported if necessary by laboratory or other diagnostic tests".

Which means that here in the UK, a vet cannot simply give his blessing to the supply of antibiotics over the phone, for example.

Jepson goes on to explain that there are four categories of medication covered by the 1968 Act. These are:

POM (Prescription Only Medicines). This group includes all antibiotics in the UK, including those such as tetracyclines that are more freely available in the US, for example. It also includes metronidazole, the premier treatment for Discus with Hole In The Head Disease. For use in fishes, a veterinary surgeon must prescribe these, after examination of the diseased fishes in question.

PML (Pharmacy and Merchant List)

P (Pharmacy). Both of these categories can be legally sold by either a veterinary surgeon, a pharmacist, or an agricultural supplier. However, if the retailer is a veterinary surgeon, the same restrictions apply to these categories as to POM category medicines.

GSL (General Sales List). This contains medications that can be sold without restriction, including such items as de-worming medicines for dogs that can be sold through pet shops, or even supermarkets. This of course includes all of the proprietary fish medications such as Melafix, Myxazin, Protozin and the others that form the stock in my fish medicine cabinet (and which are fortunately used only rarely!).

Now of course, quite a few aquarists develop an in-depth body of knowledge with respect to fish diseases. Some even possess microscopes, laboratory equipment and are able to perform their own histological and pathological tests. Some have enough knowledge of fish biology to perform post mortem examinations of their own. However, even with that body of knowledge, they are still, here in the UK, restricted with respect to access to antibiotics, whose dispensing is controlled for very sound reasons. First, uncontrolled dispensation has been the underlying driving engine behind multiple disease resistance: even here in the UK, with strict controls in place, MRSA in hospitals is a major issue, and would be even more so if uncontrolled dispensing had been in place. Second, in the case of veterinary antibiotics, some of these will, during the course of veterinary practice, find their way into the human food chain. The scope for litigation should such medications be dispensed in other than a strictly controlled fashion is, frankly, frightening to contemplate, and that is before one considers possible medical consequences of misuse, both in animals and in humans eating meat from livestock thus treated.

Furthermore, there is the complication of administration of antibiotics to fishes. While some are readily soluble in water, others are not, and thus administration has to take other forms. Firstly, the use of medicated food, which introduces a fairly large uncertainty with respect to dosing levels, unless one has access to a certain sophistication of equipment. Can you say absolutely for certain, for example, that your fishes are receiving the specified dose of 5 milligrams per Kg of body weight that the manufacturer recommends, when you're mixing the antibiotic with TetraMin flakes by hand? Second, direct injection. Apart from the other legal issues surrounding the possession of hypodermics by the lay person (an issue that is a sore point with numerous diabetics here in the UK), while a hypodermic allows a precisely metered dose to be administered, how many of us have the skill and knowhow to inject a fish safely? It's bad enough with something like a Koi from a pond, where you're dealing with a large body, and therefore something easier to handle. Try administering an intravenous injection to a Neon Tetra, and you'll pretty quickly discover the level of skill involved in doing this correctly!

To add to the complications, several antibiotics are licenced for use in highly specific circumstances. Some are licenced for one animal species only (e.g., dairy cows), and for very specific disease instances. Using these products 'out of licence' (i.e., in another species, or in another disease instance) is fraught with legal ramifications: another reason why this responsibility is restricted in law (in the UK at least) to veterinary surgeons, who are given the legal mandate to do so if their clinical judgement dictates this. Jepson cites as an example apposite to aquarists the use of dimetridazole as an alternative treatment for Hexamita in Discus, which worked, but also resulted in sterility in numerous fishes thus treated.

This issue becomes most prominent when the antibiotic in question is one licenced solely for human use. In this case, other sections of the Medicines Act come into play. Some of the medicines licenced solely for human use are subject to additional constraints, and for very good reasons. For example, Vancomycin, one of the glycopeptide antibiotics (the other principal member of the family being Teicoplanin) is not only restricted for human use, but further restricted as a 'hospital only' antibiotic, that can only be dispensed under strict clinical supervision. First, because it is the only antibiotic that will successfully treat some strains of MRSA, and doctors are anxious to preserve the utility of this last remaining weapon in that particular battle. Second, because in humans, severe side effects have been recorded, including kidney failure in some particularly sensitive patients. Do you have the requisite knowledge in molecular biology to state categorically that similar metabolic pathways won't be adversely influenced in your Cichlids if Vancomycin is ever administered to them? Precisely. Which all helps to explain why veterinary surgeons can spend seven years in intensive study before emerging from veterinary school with those all-important initials 'MRCVS' after their names.

As Jepson states, the tropical fish hobby is, in addition, too small a market for most pharmaceutical companies to justify financing the appropriate research. In the case of dairy cows, the market is huge, and subject to strict legal controls (including legally binding international treaties) because the last thing that any government, or any responsible human being for that matter, wishes to see is mass poisoning of milk consumers, for both legal and humanitarian reasons. Even without those legal requirements, the existence of something like 10 million dairy cows in the UK alone, and their continued use in the human food chain, guarantees a decent return on research investment. Aquarium fishes, on the other hand, constitute a market whose size is practically subatomic in comparison. To illustrate this, the payoff for investing in new and more effective treatments for brucellosis in cattle (a nasty disease which has, in addition, human health inplications) is likely to be enormous, while that for dealing with Pesudomonas bacteria in fishes in a clinically certified manner is by comparison minuscule. Even in the case of fish farms such as the salmon farms in Scotland, where there is likely to be reasonable payoff (again because human food issues are involved), the rewards pale into insignificance beside those resulting from research into food-chain livestock.

Finally, there is cost. Some antibiotics are expensive. Even if access to a product such as Methicillin (one of the advanced synthetic penicillins) was not constrained by the above legal and medical issues, chances are that the cost would be prohibitive to anyone obtaining the antibiotic for use in something other than prize show Discus, Cyphotilapia frontosa or deep-water marine Angelfishes such as Paracentropyge boylei, which here in the UK costs about the same as a second-hand BMW car, and therefore justifies considerable expense in keeping it alive. Consequently, even though Methicillin would amply serve its purpose in eliminating a bacterial infection in fishes, it is unlikely to be pressed into service to treat a shoal of Zebra Danios that collectively cost less than £5 to buy in the first place. And, as mentioned above, Vancomycin and one or two other antibiotic exotica are in such demand for critical human health issues, that even without legal restrictions on purchase and use, the cost is likely to be astronomical, to the point where even the Paracentropyge boylei owner might pause for a moment before writing out the cheque.

Hopefully, this should answer a few questions for the curious


Panda Catfish fan and keeper/breeder since Christmas 2002

Cal, we have to get you to put some of these reads into bonafide articles to be stored under either the Articles section or the FAQ section. Its ashame that in a matter of weeks, this will fade away, unless it is made a sticky. Ditto with the many detailed articles you write on fish. Those should be stored under articles. Have you considered it?

Thanks for explaining the issues as they are in the UK with regards to meds. I knew it was not easy to get antibiotic without going to a vet, but didn't know the details.

I do know that some of our members have had luck getting a bag of tetracycline powder, for example, after taking in pictures and showing similar symptoms from a book. We had one goldfish that was chronicall sick and the egg-white, powder (TC) coated pellets, did the trick. It is guess work, in terms of getting them to eat just the right amount, or making it in a way that it doesn't float away. In fact, the person who cured the fish was able to hand feed her goldie so that the pellets weren't on the water very long at all.

Cory_Di, Adam has several of my big posts as articles waiting to roll that I mailed him some time ago. Perhaps if you tap him and Lindy on the shoulder

Panda Catfish fan and keeper/breeder since Christmas 2002