Bacterial Infections

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Humblefish

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Why fish get bacterial infections

What You Need To Know:

* Infections can be caused by either Gram‐positive or Gram-negative bacteria. Gram-negative infections are typically more virulent, and more common in marine fish.
* Bacterial infections are often "secondary" to a preexisting parasitic or worm infestation.
* Poor water quality, open wounds and nutritional deficiency (which lowers the natural immune system) are all possible contributing factors of infection.
* Best treatment for a bacterial infection is a broad-spectrum antibiotic: Antibiotics

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Additional Information

We all know the water in our aquarium is full of bacteria. Most of it is good (like nitrifying bacteria), but certain strains can be harmful to aquatic animals. This "bad" bacteria is usually kept at bay by a healthy fish's natural immune system. Or if the fish becomes sick and displays symptoms of a bacterial infection, sometimes the immune system is still able to fight it off without the aid of antibiotics. So if you stop and think about it, these bacterial infections in fish are akin to our own never-ending battle with germs, viruses, and of course, infections.
;)


Many factors make a fish more susceptible to infection. First, a cut or open wound is usually required for infection to set in. Even tiny "bite marks" left by feeding parasite trophonts can get infected. Poor water quality is also usually a key ingredient which increases the odds of a bacterial infection. Also, anything that lowers the fish's overall immune system makes infection more likely. Stress (e.g. fish fighting), malnourishment, or if the fish is battling an ongoing parasitic or worm infestation makes a "secondary" bacterial infection more possible. For example, back when I practiced "Ich management" it seemed periodically I would have a fish develop a cloudy eye or some suspicious red mark. Now that I quarantine (QT) and prophylactically treat all my fish, I almost never see anything like that once the fish enters my display tank (DT). Disease-free fish are healthier and more capable of overcoming potential infections.

Gram positive vs. gram negative: Unfortunately, the majority of bacterial infections in marine fish are caused by gram-negative bacteria. These are typically more virulent than infections caused by gram-positive bacteria. When a fish does have a gram-positive infection symptoms may be so mild that they are unnoticeable. The only way to differentiate between the two is to take a skin scrape of the affected area and gram stain it (more info). Gram-positive bacteria stain blue, and gram-negative bacteria stain pink.

Gram-negative infections are nothing to play around with. In fact, some fish can die within 24 - 48 hours of showing symptoms due to the aggressive nature of some gram-negative bacteria. These strains can easily overwhelm the fish's natural immune system. So, what does a bacterial infection look like? Symptoms may include:
  • Any "redness" or open sores/wounds on a fish should be viewed with suspicion.
  • A white film or "fungus" looking growth can denote a bacterial infection.
  • Frayed fins / fin & tail rot.
  • Cloudy eyes
  • Bloating can denote an internal bacterial infection.
However, it is important to note that the symptoms listed above can also mean something entirely different. For example, a white "cauliflower-like" growth on the fins & spines is most likely just Lymphocystis, a harmless virus found in many fish. Redness around the gills is a symptom of ammonia burn, while open red sores on the fish could be Uronema. So, doing proper research and not just lumping everything into one category is vital. Whether or not a bacterial infection is contagious is highly dependent upon the strain you are dealing with and the conditioning of your other fish. So, there is no easy answer.

Treatment Options - First off, there are many things you can do to prevent a bacterial infection from happening in the first place. Some of these include:
  • Maintaining a proper environment (i.e. clean water) for your fish to live in.
  • Separating two quarreling fish before cuts/wounds get too serious.
  • Utilizing proper nutrition (e.g. live foods, nori, frozen foods high in protein), and soaking fish food with vitamin supplements (e.g. Selcon, Zoecon, Vita-chem). These will help boost your fish’s natural immune system.
  • Utilizing a fish Quarantine Tank - to prevent parasites and other nasties (including harmful gram-negative bacteria) from ever entering your DT. This will alleviate the possibility of a "secondary" bacterial infection popping up while the fish's immune system is already compromised from battling parasites/worms.
  • Running a UV sterilizer or Ozone may help in certain situations, as that will lower the overall number of harmful bacteria found in the water column.
When to medicate: Sometimes all the vitamins, proper nutrition and clean water are just not enough. Sometimes a fish's natural immune system needs a helping hand (like our own). When to QT and pull the trigger on using antibiotics is not an easy decision; it's a judgment call.

As a general rule, I only pull & treat if: (a) The fish looks really bad or (b) It is a newly acquired fish showing signs of infection. The latter is an easy call for me as I QT all new fish anyway. Here is a list of antibiotic medications you can use: https://humble.fish/community/index.php?threads/antibiotics.15/

More info about specific antibiotics: http://www.americanaquariumproducts.com/AquariumMedication2.html

I also recommend giving the fish a 90 minute bath using Ruby Reef Rally en route to quarantine. Although it is not optimal to do so, you can combine antibiotics with copper treatment or Chloroquine phosphate. Since I do not use hyposalinity to treat Ich, I have no experience using antibiotics in hypo conditions. I do not recommend mixing Prazipro with antibiotics. It is important to remember that every medication you use depletes the water of oxygen. Combining meds just exacerbates this. Therefore, it is absolutely imperative to provide additional gas exchange when treating; by pointing a powerhead towards the surface of the water or running an air stone on high.

DO NOT overdose antibiotics; if in doubt, always underdose. Antibiotics can be harsh on and even kill certain fish; although appetite suppression is much more common. Antibiotics will kill some of the nitrifying bacteria in your bio-filter, but rarely wipes them all out to the point where you see an ammonia spike. However, for this reason and the negative impact antibiotics can have on corals/inverts, I strongly discourage their use in a DT.

More information below:

Use of Antibiotics in Ornamental Fish Aquaculture

Bacterial Diseases of Fish
 
Question I'll never catch him. Ever. Anything reef safe like soaking food antibiotics. Water quality is great. Lrs food. I'm dosing vitamins. Now I'm dosing extra selcon with lrs. But if I have to try meds. Anything safe for tank
 

Humblefish

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Using a shot glass:
  • 1 scoop (~ 1/8 teaspoon) of medication (Seachem Kanaplex)
  • 1-2 scoops Seachem Focus (makes it reef safe + binds the medication)
  • 1 Tbsp food (preferably pellets or frozen food)
  • A few drops of saltwater or fish vitamins
  • Stir until a medicated food slurry has been achieved.
  • Feed after soaking for 30 mins.
  • Refrigerate or freeze any leftovers for future use.
  • You can feed this mix 1-2 times per day. Not recommend to exceed 2 feedings per day with medicated food.
 
These dwarf angels have been in qt for 16 days and have gone through hybrid ttm with 3 sixty minute formalin baths (heavy uronema upon arrival)....praziquantel and metro soaked food. kan/met/furan for five of those days. 60 minute enrofloxacin at 35g/gal.

They still seem to be declining. Breathing heavily. There are five being kept in 25 gallons (hope to move all five to 600 fowlr), frequent w/c and prime. lots of pvc to curb aggression.

Most recent scrape on the saddest looking had ONE uronema specimen which I searched long and hard for so there doesn't appear to be a heavy parasitic infection.

There is a noticeable white sheen on their sides which is potentially suspect, but this is the first time I've cared for this species so I'm always hesitant to jump to conclusions based on color...

Anyway, did a gram-stain of a scraping. I'm not really sure how to interpret it. Both photos are the same sample and at 1000x.
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Dierks

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Hmmmm......

I wonder if you are dealing with Vibrio instead of urinoma. They appear very much the same but Vibrio. Yet you said you seen Uronema under the scope and Vibrio is Gram Negative. With your purple results that should mean gram positive I believe....

I personally would try Ciprofloxacin if you can get your hand on it.
 
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Hmmmm......

I wonder if you are dealing with Vibrio instead of urinoma. They appear very much the same but Vibrio. Yet you said you seen Uronema under the scope and Vibrio is Gram Negative. With your purple results that should mean gram positive I believe....

I personally would try Ciprofloxacin if you can get your hand on it.
Do ciprofloxacin and enrofloxacin not utilize similar/the same mechanisms to suppress infections?
 

Dierks

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Yes they do - But I believe you said you only did it one time? I believe it requires several weeks (5-7 baths every other day) @Humblefish is this correct? Also what are your thoughts on the above. What is a Gram Positive bacteria that could be mistaken or in conjunction with uronema?
 
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Humblefish

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Do ciprofloxacin and enrofloxacin not utilize similar/the same mechanisms to suppress infections?
Did you dose Enrofloxacin directly into the QT or do bath treatments? The biggest advantage Ciprofloxacin has over Enrofloxacin is the former can be administered at a much higher dosage (250mg/gal) in a 1-2 hour bath treatment. The only dosage info I've found for Enrofloxacin is 10 – 20 mg/gal dosed daily. I haven't experimented with any bath treatments for that medication.

Your gram stains show both gram-positive and gram-negative bacteria on the fish. :( So, combining kanamycin with nitrofurazone might be a better treatment option here.
 

JCTReefer

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When to QT and pull the trigger on using antibiotics is not an easy decision; it's a judgment call.

As a general rule, I only pull & treat if: (a) The fish looks really bad or (b) It is a newly acquired fish showing signs of infection. The latter is an easy call for me as I QT all new fish anyway. Here is a list of antibiotic medications you can use:
Yesterday I completed day 16 of HTTM. Went ahead and did that extra transfer as an extra precaution. The Hippo’s spots that we had discussed in a different thread have not returned. After the second H202 dip they never came back. This was 8-12-21 when the second bath was done. So 8 days ago. The tang is FINALLY eating well also. :DIt’s about time!!! After 22 days it decided to eat.. The Damsels fins are still a bit frayed and ragged. Some look better than the others. There’s also a small protrusion Right below on one the damsels dorsal fins. And one of the other damsels has some large white spots on its head. Not ich, but I’ve seen this before. Matter of fact, my 4 year old azure had this exact issue when I was quarantining it in 2017. These spots “self corrected“ once in the DT. Still have pictures of those spots on my phone. Could have been viral or bacterial.🤷🏼‍♂️ There’s some slight redness towards the Foxface’s caudal fin.

Now that the fishes are in their “final observation tank”, I’m trying to decide whether or not to start antibiotics. Bad bacteria should be pretty low in numbers I would think. Matter of fact, when I had my Qt tested by AquaBiomics, bad bacteria was “non existent”. The fish have been kept in pretty clean water being transferred so many times. I know it’s a judgment call on my part on medicating. My gut tells me the ragged fins and spots will go away with time, good nutrition, and water quality. The redness I’m seeing on the Foxface could be my eyes playing tricks on me. Same thing with that CB yellow tang. Noticed redness in the same area on that fish. No issues after transferring to DT. It’s bizarre how the Foxface can change colors on the drop of a dime. Not sure if this holds true for all rabbit fish.
Meds on hand are Kana, Furan, Metro, Cipro, and Spectrogram. I’m on the fence on whether to treat just yet. I mean the hippo is finally eating and I hate to start throwing antibiotics in the water that might effect its whole gut microbiome. At what point do you decide to pull the trigger when it comes to treating? Would you always treat at the first signs of something suspicious? I know you’ve quarantined a ton of fish in your lifetime. That’s why I’m asking!!!
UPDATE. I went ahead and dosed my first round of spectrogram. Instructions say to double dose for marine. And do 3 treatments spaced 2 days apart. I have just enough to do that. Unfortunately spectrogram has been sold out for several months due to Covid they said.
 
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JCTReefer

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@Dierks Have you ever seen anything like this come in on any of your shipments? Don’t know how much you deal with damsels. I’m sure you’ve seen a lot of fish over the last few years. Does this look bacterial or viral??? I don’t think I’ve seen anything exactly like this before. Thought I’d ask. It’s protruding on both sides. And in two different locations along its dorsal fin. I can post a quick video if that would help see things better. Was hard getting a good pic with the water being so yellow. The camera filter did help and it’s pretty close to what it looks like in person. Currently treating with Spectrogram(Kanamycin/Nitrofurazone)
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Dierks

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Good Call on the Spectogram -- I would also add in Metro as well. I thin I see some pealing behind the white dot. Will just get you cover for everything (y)

MB would be the treatment for fungus, but I am not sure that is what it is. It almost looks like the "zits" that we see on clownfish a lot. Most the time the treatment is exactly what you have them in with the addition of metro. If they grow and then burst they are cyst's, you will want to keep the fish in its own tank if at all possible, if you notice this as those can release thousands of spores into the water.

I think that is about all I know?!? Maybe @Humblefish can put his eyes on it as well.
 

JCTReefer

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Good Call on the Spectogram -- I would also add in Metro as well. I thin I see some pealing behind the white dot. Will just get you cover for everything (y)

MB would be the treatment for fungus, but I am not sure that is what it is. It almost looks like the "zits" that we see on clownfish a lot. Most the time the treatment is exactly what you have them in with the addition of metro. If they grow and then burst they are cyst's, you will want to keep the fish in its own tank if at all possible, if you notice this as those can release thousands of spores into the water.

I think that is about all I know?!? Maybe @Humblefish can put his eyes on it as well.
I noticed another damsel had the large white zits on it’s head. Smaller in size. I’ve seen those before. Those seem to “heal” on their own. Will add metro to the mix for good measure. I do my third and last treatment on the spectrogram tomorrow. According to the instructions that is. Bad thing is, I can’t get anymore, and the third treatment will use most of it up. They’ve been out of stock on that product for a long time. I emailed them a while back and they had no clue as to when it might be available again. Covid related😫. Here’s a little video.
 

Dierks

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Looks like cyst -- You can see it sticking out in this frame:

Fish1.jpg


@Humblefish what are your thoughts? Also you can make your own Spectrogram -- Hard to find Furan 2 right now though. I think I have some Spectrogram in my stanches if you need more.
 

JCTReefer

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Looks like cyst -- You can see it sticking out in this frame:

View attachment 38875

@Humblefish what are your thoughts? Also you can make your own Spectrogram -- Hard to find Furan 2 right now though. I think I have some Spectrogram in my stanches if you need more.
I do have some Furan 2, Kana, and plenty of Metro👍. You’re definitely right on the Furan. I couldn’t find that stuff anywhere. Wonder what gives. Probably covid 🤣. Glad I bought some a while back.
 

Humblefish

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@Humblefish what are your thoughts? Also you can make your own Spectrogram -- Hard to find Furan 2 right now though. I think I have some Spectrogram in my stanches if you need more.
It could be a bacterial related cyst. However, I've also seen Uronema pop up on Kupang Damsels like this.
 
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