# Medications which affect Beneficial Bacteria



## Fishy_Cichlid (Aug 4, 2011)

Have been lately doing a lot of research on fish and tank whilst my tank is cycling. Nothing is giving me more pleasure really. So I would like to share some important tit-bits with members of the forum, discuss if necessary, and for general knowledge of all members here in C-F.

So here is something I found out from from a very reputable Aquarist+Breeder+Designer. Kindly comment on his observations.

Some medicines whilst killing your unwanted pathogens will also kill a lot of the beneficial bacteria. Some of them are :
1. Chlorotetracyclene (10 mg/L)
2. Oxytetracyclene (50 mg/L)
3. Formalene has variable effect on the N2 cycle (15-25 mg/L)
4. Methylene Blue (1-8 mg/L) can have severe and prolonged interruption to the N2 cycle

Some medications which will leave the N2 cycle unharmed are :
1. Copper (0.5 mg/L)
2. Nifurpiririnol (upto 1.0 mg/L)
3. Sulphamerazine (upto 50 mg/L)

The author also goes on to say that the best & preferred way is to remove the affected fish to a quarantine tank and do 80% water change on the tank.


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## Jammos (Nov 25, 2010)

Yes and no. Its a good topic to discuss. I will give you my view as a Microbiologist (not a tank expert). The good bacteria form what s known as a biofilm which is a community of bacteria adhered to your substrate of choice. This biofilm is highly complex and protective of itself through extra polysaccharide outer layer. Such biofilm make it difficult for antibiotics or antimicrobials to penetrate them. So while in theory I would doubt the good bacteria are so effected by these treatments. Of course continued treatment may increase these chances.

Dental plaque is a form of biofilm and just consider how difficult it us to remove it...you Need a toothbrush!

If your good bacteria and their biofilm are well established there should (IMO) be little risk from the usual fish treatments for disease

James


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## GTZ (Apr 21, 2010)

In general, meds that are effective against gram-positive bacteria will be harmful towards your beneficial bacteria, in varying degrees.
Luckily, most bacterial infections in freshwater fish are gram-negative as are the majority of meds.


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## 13razorbackfan (Sep 28, 2011)

Jammos said:


> Yes and no. Its a good topic to discuss. I will give you my view as a Microbiologist (not a tank expert). The good bacteria form what s known as a biofilm which is a community of bacteria adhered to your substrate of choice. This biofilm is highly complex and protective of itself through extra polysaccharide outer layer. Such biofilm make it difficult for antibiotics or antimicrobials to penetrate them. So while in theory I would doubt the good bacteria are so effected by these treatments. Of course continued treatment may increase these chances.
> 
> Dental plaque is a form of biofilm and just consider how difficult it us to remove it...you Need a toothbrush!
> 
> ...


Interesting....how about rinsing used filter cartridges under warm tap water(chlorinated)? Does the chlorine kill on contact or is the nitrifying bacteria more resilient than we think?


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## Fishy_Cichlid (Aug 4, 2011)

Hi GTZ,

Could you tell us for which bacterial infection/medication (Ich or whatever) is caused by 'Gram Negative Bacteria' so that for those infections, we can treat the fish outside the aquarium water. Anything specific to check in the medication specification which will indicate a 'gram negative bacteria' ?

Jammos, I have also read that the biofilm formed in the media/substrate due to the Nitrifying bacteria isnt all that durable, specially so, when the biofilm is newly formed like immediately after cycling. Your insights as a microbiologist will be very valuable to us.


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## Jammos (Nov 25, 2010)

13razorbackfan said:


> Jammos said:
> 
> 
> > Yes and no. Its a good topic to discuss. I will give you my view as a Microbiologist (not a tank expert). The good bacteria form what s known as a biofilm which is a community of bacteria adhered to your substrate of choice. This biofilm is highly complex and protective of itself through extra polysaccharide outer layer. Such biofilm make it difficult for antibiotics or antimicrobials to penetrate them. So while in theory I would doubt the good bacteria are so effected by these treatments. Of course continued treatment may increase these chances.
> ...


Chlorine will kill on contact and at the right levels will penetrate biofilm - it is used that way in sanitizing piping in manufacturing plants. So be careful!


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## Jammos (Nov 25, 2010)

Fishy_Cichlid said:


> Hi GTZ,
> 
> Could you tell us for which bacterial infection/medication (Ich or whatever) is caused by 'Gram Negative Bacteria' so that for those infections, we can treat the fish outside the aquarium water. Anything specific to check in the medication specification which will indicate a 'gram negative bacteria' ?
> 
> Jammos, I have also read that the biofilm formed in the media/substrate due to the Nitrifying bacteria isnt all that durable, specially so, when the biofilm is newly formed like immediately after cycling. Your insights as a microbiologist will be very valuable to us.


That is logical. Newly formed biofilm is more suceptible then well established biofilm. Bacteria adapt all the time and will become more resistant especially when subjected to low levels of an antimicrobial.

Medications will state whether they are effective against parasites, gram, positive or negative bacteria. If they don't you can look it up. Some will be effective against both, rarely against all three. Gram is just a classification of bacteria based on their cell wall structure. As already said gram negatives are more typically disease causing just like E. coli and Salmonella in humans


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## PfunMo (Jul 30, 2009)

Interesting subject but one that will lead our thinking in many different directions. When bio-film and chlorine are mentioned it has always been of interest to me how the bacteria in our tanks (good bacteria) differ from the bacteria in septic systems so commonly used. We are often told not to use tap water because it will kill the bacteria. But then closed septic systems like places where there is not a public sewer available, use bacteria to convert the waste. Is the bacteria that different or is the harm from chlorine that overblown? It is pretty standard practice to use chlorinated water and run the entire load from a house directly into the septic tank. If chlorine kills on contact, why is the bacteria in septic tanks not killed every time we take a shower?


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## Jammos (Nov 25, 2010)

PfunMo said:


> Interesting subject but one that will lead our thinking in many different directions. When bio-film and chlorine are mentioned it has always been of interest to me how the bacteria in our tanks (good bacteria) differ from the bacteria in septic systems so commonly used. We are often told not to use tap water because it will kill the bacteria. But then closed septic systems like places where there is not a public sewer available, use bacteria to convert the waste. Is the bacteria that different or is the harm from chlorine that overblown? It is pretty standard practice to use chlorinated water and run the entire load from a house directly into the septic tank. If chlorine kills on contact, why is the bacteria in septic tanks not killed every time we take a shower?


Many of the bacteria in septic tanks are known as spore forming bacteria. Bacillus being one of them. These type of bacteria are some of the hardiest bacteria known and are quite resistant to chlorine especially when it is watered down so much. If you consider the product 'Rid X' - that stuff is simply Bacillus spore forming bacteria plus additional enzymes to help digest the waste, and a lot of people use it to 'feed' their septic system. On top of that septic systems have their sludge excreted by the bacteria which aid in protecting them from chlorine. Consider a septic system the ultimate biofilm!


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## PfunMo (Jul 30, 2009)

Okay! sounds like a good answer. Different bacteria doing a different thing. As far as the ultimate part, I had thought it was the ultimate something but not bio-film!! Thanks.


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## Fishy_Cichlid (Aug 4, 2011)

So the biofilm acts as the protective coating for bacteria. However, I think this Biofilm will be of different thickness/resilience for different types of bacteria. And the matter in question is whether this Biofilm is thick enough in case of Nitrifying bacterias.

Incase of freshwater tank, we often see mini cycles in the tank of members even after cycling. In some cases it could be that not enough bacteria was formed during cycling but there have been cases where there have been spike in older tanks too ....... maybe because it was neglected a bit. Does that imply that the film is not resilient enough in case of Nitrifying bacteria ??

In freshwater tanks, we are often worried about power outages ...... since the Nitrifying bacteria is a aerobic bacteria and needs a source of supply of food. However, Septic tanks remain unused in houses lying vacant for years or even when we go off for long holidays. The Bacteria does not die off. Something just tells me that the bacteria in our aquariums are just not strong enough to sustain longer period without food supply and that the film too isnt robust.


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## GTZ (Apr 21, 2010)

Getting back to different bacteria as infections, quite often gram-positive infections are eye related (cloudy, milky), and Erythromycin (gram-positive) is the drug of choice. Medications like Erythromycin, Tetracycline, Minocycline and to a lesser extent Melafix, are also primarily gram-positive treatments. When medicating an aquarium, I usually recommend periodic testing of all water parameters. When treating with the aforementioned meds, I would test daily and have backup bio media ready in case it's needed.


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## Fishy_Cichlid (Aug 4, 2011)

Gram-negative bacteria are pathogenic in nature, since they can cause disease in a host organism and have a thin cell wall. Gram negative bacterial infections are much more common in fish, especially marine.

Some Gram Negative Bacteria:
- Aeromonas (anaerobic)
- Furunculosis; Aeromonas-salmonicida (anaerobic)
- Vibrio (anaerobic)
- Flavobacterium (Columnaris) (aerobic)
- Pseudomonas (aerobic)
- Streptobacillus (anaerobic)
- Salmonella (anaerobic)

Gram-positive bacteria do not always cause a disease in the host organism and have a very thick cell wall. Gram positive infections are less common in fish (or aquaria in general).

Some Gram Positive Bacteria:
- Mycobacterium (aquatic tuberculosis)
- Streptococcus (aerobic)
- Pseudonocardia (anaerobic)
-Staphylococcus (aerobic)
- Cyanobacteria (Oxygenic Phototrophic)

Coming to the issue of Nitrifying bacteria which are Aerobic Chemolithotrophic Bacteria :
- Nitrobacteraceae (aerobic)
- Nitrobacter (aerobic)
- Nitrococcus (aerobic)
- Nitrospina (aerobic)
- Nitrospira (aerobic)
- Nitrosococcus (aerobic)
- Nitrosolobus (aerobic)
- Nitrosomonas (aerobic)

Anaerobic Chemotrophic Bacteria
- Erythrobacter (anaerobic)

Another issue of importance is whether the antibiotic mediaction will kill the Nitrifying Bacteria inside the tank. So how do medications affect the beneficial bacteria ?

Antibiotics killing the nitrifying bacteria is ONLY true for gram positive antibiotics or overuse of others. Most true nitrifying bacteria (Autotrophic bacteria) are gram positive whilst the majority of aquarium infections are gram negative. So use of gram positive antibiotics such as Erythromycin has a greater risk of a nitrifying bacteria die-off than Kanamycin (which is both gram negative and gram positive, however it is more effective against gram negative bacteria). Some antibiotics are mixed. Ex. Tetracycline families, which are often equally divided such as Minocycline; however Tetracycline Hydrochloride is primarily a gram positive.

Erythromycin and Ampicillin are gram positive bacteria and can be harmful to beneficial bacteria. Erythromycin is also effective for Cyanobacteria.

Diseases in the aquarium can be of 3 types - Parasitic, Bacterial & Viral. Parasitical infection in most cases may be treated with Bath treatment. For Bacterial infection, antibiotics or a combination may work. However, for Viral infection, personally, I am very doubtful of the effectiveness of Antibiotics. Like in the case of humans, the antibodies within our body fight against these viruses. This disease last for 4-5 days and subsides on its own. Antibiotics have no effect on its treatment. Antibiotics are given during Viral infection not to treat it, but to prevent any other secondary infection which may arise during the course of treatment.

Some precautions to be taken during medication -
1) Remove Carbon (& some other chemical filter media)
2) Water Changing :
Changing water immediately prior to each treatment can improve the effectiveness and lower the possible toxicity of treatment. Organics present in the tank water can absorb the medication and thus reduce the effectiness of the medications. A 20% or larger, water change is recommended before medication. Some medications break down after 24-48 hours and can leave mildly to moderately toxic chemicals behind which a water change (or even running carbon in a filter for an hour or two) prior to the next treatment can help lower/remove.


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## Fishy_Cichlid (Aug 4, 2011)

Amazing .... the more I read and try to find out, the more I am surprised by the fact that even commercial companies are now turning towards natural therapy for treatment of fish diseases. An increased tendency towards Herbal medicines. Perhaps this can be attributed to the search for a medicine/cure which is more gentle in nature on the small fishes.

For Ex. the Tea tree or Melaleuca alternifolia ... the oil extracted from this tree is both Anti-fungal and antibiotic. Its just that when we purchase the medications from shop shelfs, we are unaware of the product itself. Diluted solutions are used to treat bacterial and fungal infections in fish. The oil is actually used to promote fin and tissue regrowth but is also effective against Fin-rot or Velvet. Basically it acts like an antiseptic. hahaha, i know it would surprise many of you, if I told you that this is the ingredient used in Melafix. However, it is more effective against gram-positive bacteria which are much less common aquatic disease.

Then consider Usnea Lichen which is looks like Moss and often called Treemoss or Beard Lichen. It is effective against bacterial, fungal and even parasites. Its effective mainly against gram-negative bacteria. In my country, lichens are used to preserve spices used for cooking, and even as cosmetic products for hair !!! And say what, it is even used in the production of diapers for babies, LOL.

The Pimenta extract is effective for a broad range of bacterial and fungal diseases. It is the extract from the West Indian bay tree (Pimenta racemosa, called Pimenta acris or Caryophyllus racemosus in old references), also known as the Bay Rum tree. It is used as a treatment against fin and tail rot, mouth fungus (often caused by the bacterium Flavobacterium columnaris); fungal fish diseases (such as those caused by microorganisms of the genera Saprolegnia and Achyle) and the like. Pimenta Extract has shown to be more effective against gram negative bacterial infections which are more common in aquatic infections, the extract being sold under the brandname Pimafix. This generally makes Pimafix a better choice over Melafix (effective against gram-positive bacteria), although both may be combined.

Coming back to synthetic drugs, Sulphas tend to be a better medicine (i.e. if they work well on a particular disease) because *they are not absorbed by the cells of the fish and work extracellularly *...... thus making it more safe for use in aquariums. They act outside the fish cell structure and kill the bacteria by starving it of food. What it does is that it arrests cell growth by inhibiting the synthesis of Folic acid ..... just like human cells need Folic acid for growth & development. And yes, Sulphas are effective mainly against gram-negative bacteria.


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## PfunMo (Jul 30, 2009)

What you notice about companies leaning more toward "natural' treatments can be due to different thinking. One might be that they feel the medicine works better. The other might be due to them thinking the medicine marketed as "natural" SELLS better. There is quite a large wave of public thinking currently which makes people search for the more "natural" method. This is seen with the sudden growth of whole grain and organic products. It is not necessary to prove that they work better, if the public simply thinks they are better. Some are, some not but from the marketing standpoint it is currently a winning point to point up natural products. Since much of the research is done by or paid for by the companies who sell the product, there is some doubt in my mind whether we get the true answer. When thinking of medicine, I try not to lean to far in either direction until there is a real indication of which might be better.

The current thinking in medicine always brings me back to thinking about the term "laudible pus" which was highly thought of at the end of our United States civil war. The most highly trained medical staff assured us it was great!


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## Fishy_Cichlid (Aug 4, 2011)

PfunMo you could be right, just a marketing ploy. 
Natural products may not give instantaneous results but prolonged use certainly prevent disease. Just like Homeopathic treatment. No side effects, slow ...... however not meant for emergency or for major diseases.

You got me thinking actually ..... Take these products which claim to maintain slime in the body of the fish by addition of Aloe Vera .... marketed as products like Stress Coats etc. 1st - Aloe Vera though slimy will dissolve in the water. 2ndly, the slime coat needs to be produced at an optimal quantity. Just like human, where too much secretion of mucous which is a result of an infection lead to other medical problems. Similar is the case of secretion of excess slime in the body of the fish. However, I have read, what remains untold is that besides the Aloe Vera, these products also contain as ingredient such as Thiosulphate (dechlorinator), carboxymethyl cellulose (supposedly induces to create slime), polyvinylpyrrolidone (coating ingredient), ethylenediaminetetraacetic acid (chelating agent), tris(hydroxymethyl)aminomethane - Dechlorinator for Chloramines, diazolidinyl urea (natural preservative to help control the growth of bacteria and other microorganisms) and deionized water.

Many of these ingredients if not used/reacted upon by the fish cells, will result in excess organisms in the water which actually might deteriorate the quality of tank water, so quite the opposite effect to what was anticipated.

Basically, all these ingredients reduce the environmental stress by making the water more live-able, rather than actually induce better or more slime - so a happy fishy lot. And a happy fish without any stress is likely to produce the optimum amount of slime coating.


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## Fishy_Cichlid (Aug 4, 2011)

Now, isnt this great -
Best Review - Top 5 Dangerous Chemicals You Do Not Want In Your Makeup : and it lists *diazolidinyl urea* as one of the chemicals. Furthermore, it writes this -

Formaldehyde-Releasing Preservatives

Formaldehyde - used in preservation of cadavers is produced by DMDM hydantoin, diazolidinyl urea, methenamine, quarternium-15 and sodium hydroxymethylglycinate) Ã¢â‚¬â€


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## GTZ (Apr 21, 2010)

Additives that claim to promote slime coating on fish quite often do so by acting as an irritant. They do what they claim but do so in a 'back alley' sort of way.


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## PfunMo (Jul 30, 2009)

Over the years of buying many things, I have gradually formed a plan for when intensive shopping is needed. If I have questions about a product, I ask the dealer who sells that product. With that information I go ask the competitor about those claims. It is often possible for the second to punch really obvious holes in the story told by the first.

If I want to know what is good about Ford, I ask the Ford dealer. When I want to know what is bad about Ford, I ask the Chevy dealer. If neither story makes sense, I buy neither car!

Fish products are much the same. Tell me a believable story or I buy something else!


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