pale-face disease

[Peter Houde]

This is addressed primarily to Jay Hemdal.

I’m seeking help with the identification of cause and appropriate treatment of pale-face disease (my description). It appears to be contagious because it first suddenly appeared in my aquarium with the addition of a new unquarantined fish many years ago. Several fish including a tang, damselfish, and basslet instantly and simultaneously got it; others (notably a couple of clownfish that are still clowning around) didn't. If I recall correctly (because it was long ago), some other fish may have died (a couple of damselfish, clowns, and maybe tangs, but I'm guessing, I really don't remember). Of the tang, damselfish, and basslet that survived, the loss of all facial color progressed caudally a little more than the initial presentation over the course of 5-10 years, but very slowly and never caudal to the pectoral fins. However, the tang and damsel did have possibly unrelated caudal fin deterioration and the tang also exhibited severe open lesion of the caudal peduncle. Despite these symptoms lasting for years and years on end, none of the surviving fish ever showed any behavioral deficits or effects whatsoever. The tang was King of the aquarium until he finally succumbed (I had hoped he'd do so years sooner so I could restock the tank). But I gave up on waiting for the damselfish and 2 clownfish to die. They are still alive (at least 15 years old now) and were present when I added a new Paracanthurus tang, a bicolored dottyback, and a green mandarin. The tang, only, immediately began to lose facial color and experience fin deterioration.

Here's what I've tried to date. I added metranidazole and nitrofurantoin (and amino & omega-3/6 HUFA and garlic extract) to all fish food in the display tank for about two months with all fish present. I subsequently moved the tang, damsel, and mandarin (only because I could catch it; it had no symptoms) to a quarantine tank, and I sequentially (not simultaneously) treated them with a 5 min freshwater dip, extended hyposalinity, 5 successive weekly treatments of 2.5 mg/l praziquantel, 2 weeks 5mg/l copper sulfate, and 5 day nitrofurazone treatment.

Neither the damsel nor tang show improvement after 37 days in quarantine. The tang, if anything, is worse since its lateral line is now evident and it wasn’t previously. I can’t rule out HLLE either as the sole or an additional affliction, but this doesn’t seem to account for fin deterioration and the similarity to what years ago was undoubtedly contagious. Its diet includes macroalgae (I’ve seen it eat Gracilaria at least, but it takes a lot of coaxing to get it to eat nori) and omega and HUFA supplement added to frozen mysis, brine shrimp, Ocean Nutrition Formula-2 and San Fransisco Emerald Entre herbivore frozen foods as well as Easy Reef DKI pellets and flake food. There is no stray voltage, and there was no improvement after removing carbon from the display tank (an of course none in the quarantine tank).

Tank: established >25 years; FOWLR; 125 gallons (473 l); temperature 80F (26.7C); specific gravity typically 1.024 (~32 ppt, but reduced first to SG=1.020 and then to SG=1.015 since I began treatments described above); nitrate 0-15 mg/l; nitrite 0; pH 8.15; copper 0; phosphate ~0.32; KH/Alk 10.33-10.5; Ca 430 ppm; Mg 1290; stray voltage 0.1V; biological filtration (bio-balls in sump, 5-6 cm coral gravel, abundant purple coralline algae, and Gracilaria, Chaetomorpha, Caulerpa, and Penicillus macros) and protein skimmer.

Inhabitants: 2 Amphiprion ocellaris, 1 Chrysiptera parasema, 1 Pseudochromis paccagnellae, 1 Synchiropus splendidus, 1 Paracanthurus hepatus, various snails (cerithiids, Neritina, Nasarius, unidentified), 2 emerald crabs, bristle worms, tube worms (just extirpated by Ruby Reef Rid Ich and Rally Pro medications added to display tank subsequent to moving damselfish, tang, and mandarin to quarantine tank), 1 unidentified starfish (Asterina and small brittlestar outbreaks of the past spontaneously came and went), 1 unidentified bivalve, 1 unidentified hermit crab, unidentified sessile and vagile worms, unidentified colonial tunicates, unidentified encrusting sponges, amphipods (few outside of sump since I added the dottyback), copepods, glass sponges (in sump), and (nonparasitic) pseudokeronopsids.

I will be grateful for any thoughts or suggestions. Thanks in advance for your advice.

 

[BeltedCoyote]

@Jay Hemdal @ReefSquad @vetteguy53081

 

[Jay Hemdal]

Actually, the fish in the pictures all have severe, chronic HLLE. The fin damage is seen in severe cases, and usually in tangs (especially yellow and purple tangs, but also hepatus). It has been my experience that once fish reach this level of erosion, there is no way to reverse it - sorry!

Here is an article that I wrote up on the topic from research that I did back in 2011:

Head and Lateral Line Erosion (HLLE)

This article discusses studies performed regarding head and lateral line erosion in captive fishes. Specifically, carbon use and nutrition as they relate to this syndrome.

www.reef2reef.com

Jay

 

[Peter Houde]

Actually, the fish in the pictures all have severe, chronic HLLE. The fin damage is seen in severe cases, and usually in tangs (especially yellow and purple tangs, but also hepatus). It has been my experience that once fish reach this level of erosion, there is no way to reverse it - sorry!

Here is an article that I wrote up on the topic from research that I did back in 2011:

Head and Lateral Line Erosion (HLLE)

This article discusses studies performed regarding head and lateral line erosion in captive fishes. Specifically, carbon use and nutrition as they relate to this syndrome.

www.reef2reef.com

Jay

Dear Jay, Thanks for the speedy response. There are a few things that leave me perplexed. I'd kept Paracanthurus for years in this aquarium without this syndrome until I introduced an unquarantined fish, at which point a tang, 4 damselfishes, and a basslet immediately developed pale faces. A few fish that I'd had healthy for years suddenly died, including 3 damsels two of which were regular breeders. I can't account for any other change in the aquarium. That seems to suggest that the causative agent was contagious.

Jump ahead a decade to the present. The new tang pictured developed the symptoms with pretty close to the severity in the pictures within less than a week. Is that rate of progression to the point of irreversibility consistent with HLLE? I removed the carbon from my display tank, including the dust that had settled in the sump when the tang first exhibited these symptoms. The quarantine tank I moved it into has never had carbon, yet the condition has worsened as evidenced by white spots along the lateral line and continued caudal fin erosion.

TSM Aquatics has been generously holding a powder brown tang for me for the past two or more months. What do you suggest I do to ensure it doesn't quickly succumb to the same fate? It would seem to me that I've already excluded all the hypothesized causes of HLLE and taken all the steps that have been suggested to address it. I should add since I hadn't before that I've never witnessed any aggression among these six small fish. The tang is most often paired with any of the others except the dottyback.

Thanks again for your time and wisdom. Cheers, Peter

 

[Jay Hemdal]

Peter,

Yes - a week's time is to fast for a hepatus tang to go from symptom free to that degree of erosion due to any HLLE I've ever seen before. The only similar case was a public aquarium that had put their carbon inside a sand filter. This caused a lot of dust to be produced and the fish developed acute symptoms very quickly.
It is pretty common for HLLE to continue to worsen for a bit after fish have been removed from the exposed water. Removing carbon doesn't seem to work in many cases I dealt with, where a complete tear down, wash out and reset did.

This could be some odd infection, but it isn't one I've ever see before...I looked at the pictures again, I was looking at the damsel's head before, and didn't look at its caudal fin - it is all torn up. Has it been fighting? If not, there could be a primary bacterial infection going on, but again, I've never seen that cause HLLE before.

Jay

 

[Peter Houde]

Peter,

Yes - a week's time is to fast for a hepatus tang to go from symptom free to that degree of erosion due to any HLLE I've ever seen before. The only similar case was a public aquarium that had put their carbon inside a sand filter. This caused a lot of dust to be produced and the fish developed acute symptoms very quickly.
It is pretty common for HLLE to continue to worsen for a bit after fish have been removed from the exposed water. Removing carbon doesn't seem to work in many cases I dealt with, where a complete tear down, wash out and reset did.

This could be some odd infection, but it isn't one I've ever see before...I looked at the pictures again, I was looking at the damsel's head before, and didn't look at its caudal fin - it is all torn up. Has it been fighting? If not, there could be a primary bacterial infection going on, but again, I've never seen that cause HLLE before.

Jay

Dear Jay,

Of course I can’t be certain, but I’ve been operating under the assumption that the damselfish’s fin damage was not inflicted by a tank mate. Until just a couple of months ago, there weren’t even any other fish (or crabs) in the aquarium except two large clownfish. The clownfish bully one another now and then and each have a nip out of one pelvic fin, but I’ve never seen them tangle with the damsel and >99.9% of the time they are peaceful. The first two photos of the damsel that show the tattered caudal fin was taken on January 14, 2021. The caudal fin may have regenerated a bit since then, but all fins exhibit deterioration - dorsal, pectoral, pelvic, anal, and caudal. I can say with certainty that the tang’s caudal, dorsal, and anal fin erosion is spontaneous and not injuries. In fact, the distalmost margin (~1mm) of the caudal fin appears to be colorless and in a process of continued decay.

I don’t doubt your diagnosis of HLLE, but it’s a symptom that might have twice as many etiologies as there are opinions about it. I suspect something organismal because it appeared coincidentally with a new fish years ago and seemed to be highly contagious. I’ve been shooting in the dark with treatments for the past couple of months not knowing what to treat. I’d like to get the fish out of the stressful quarantine tank, especially if I’m destined to be ultimately unsuccessful anyway. But I’m willing to keep shooting in the dark if there is a chance that I can eradicate the problem so that new fish won’t be infected. There is a powder brown tang and Siganus coming eventually.

I have completed a five day treatment of nitrofurazone (~2.25 mg/l daily). I think it was stressful on the tang because it tended to rest in the corner of the quarantine tank sometimes, which it had not done before. It was also during this treatment that tiny white spots appeared along its lateral line. Those seem to have since disappeared. Do you think it might be worthwhile or too risky to repeat the treatment? Alternatively or subsequently, I have Ruby Reef’s Hydroplex on hand. I was originally optimistic about using it, but I’ve since read, whether true or not, that it contains no active ingredients. Do you have any experience treating viruses or fungi? Would you recommend a “stress coat”? Would that be contraindicated with other ongoing treatments? I’m resigned to accept that these fish may be permanently disfigured, but I am anxious to rid them and the aquarium of whatever is causing this. I'll be grateful for your advice.

One thing that has been in the back of my mind is that for many years I have developed an allergic contact rash immediately and up to a week after reaching into the display aquarium. Coincidence? I’ve never had this reaction to ocean seawater or freshly mixed saltwater, so there is clearly something irritating that is specific to the aquarium. There are no cnidarians and I can handle bristleworms with impunity.

Cheers, Peter

 

[Jay Hemdal]

Taking another look at this. Are there ANY fish in this system that do NOT show symptoms? I have a pretty good list of which species can develop HLLE and which do not, so it would be interesting to see if there is any match up there.

I wrote a short paper in 1989 titled something like "Bacterial infection apparently as a cause of HLLE". It was a case history of an angelfish that I had treated with copper for ich, that then developed what I thought was a severe bacterial infection. 30 years later, I reviewed that case and saw that I had added carbon to remove the copper and then the fish developed the erosion.

I would not bother with any of the stress coat, topical "medications". Those are all polymers and things like aloe vera that has little to know known efficacy for treating active diseases. In fact, one study showed that aloe vera was toxic to fish at fairly low concentrations.

I don't know how to advise you in regards to a redose of the nitrofurazone, I'm not sure if it can be used for a second course of treatment or not. My general recommendation is that if you try a full antibiotic treatment with no results, the issue either isn't bacterial, or you need to try a different antibiotic.

I've never used Hydroplex. Its ingredient list contains a number of compounds that I've never heard of being used in aquariums.

Jay

 

[Peter Houde]

Taking another look at this. Are there ANY fish in this system that do NOT show symptoms? I have a pretty good list of which species can develop HLLE and which do not, so it would be interesting to see if there is any match up there.

I wrote a short paper in 1989 titled something like "Bacterial infection apparently as a cause of HLLE". It was a case history of an angelfish that I had treated with copper for ich, that then developed what I thought was a severe bacterial infection. 30 years later, I reviewed that case and saw that I had added carbon to remove the copper and then the fish developed the erosion.

I would not bother with any of the stress coat, topical "medications". Those are all polymers and things like aloe vera that has little to know known efficacy for treating active diseases. In fact, one study showed that aloe vera was toxic to fish at fairly low concentrations.

I don't know how to advise you in regards to a redose of the nitrofurazone, I'm not sure if it can be used for a second course of treatment or not. My general recommendation is that if you try a full antibiotic treatment with no results, the issue either isn't bacterial, or you need to try a different antibiotic.

I've never used Hydroplex. Its ingredient list contains a number of compounds that I've never heard of being used in aquariums.

Jay

Dear Jay,

Yes, these fish never developed symptoms of facial depigmentation and fin erosion: 2 Amphiprion ocellaris, 1 Pseudochromis paccagnellae, 1 Synchiropus splendidus. The 2 clowns have been exposed for more than a decade. Two other clowns died without symptoms, but I don't remember whether that happened when other fish first developed the problem in the aquarium or whether they were just bullied to death by the larger dominant clowns (they were beaten a lot). I've had the dottyback and mandarin for only a couple of months, but I had a long-lived mandarin years ago that I believe was exposed but never exhibited symptoms. It died when I accidentally crushed it moving live rock.

These fish did develop symptoms of facial depigmentation and fin erosion: 4 Chrysiptera parasema, 2 Paracanthurus hepatus, 1 Gramma lareto. Three of the damsels died when the problem first arose roughly ten years ago, while one survived to the present with symptoms. I had only one tang at a time during the course of this scourge. The first developed the symptoms immediately with the others but survived for many years with the pale face and very severe erosion of the caudal peduncle (exposed bone and myomeres) and caudal fin. It presented no behavioral deficits, despite looking ghastly. I've had the second tang for only a couple of months, with at least two years elapsing between the two. I introduced it simultaneously with the mandarin and dottyback. The tang developed head and caudal fin symptoms within days. The basslet had long been disease free prior to the original outbreak. It also developed the symptoms immediately along with the others, but survived for many years thereafter. It expressed the pale face but no other symptoms or behavioral deficits. For what it's worth, none of the fish ever showed erosion along the lateral line, except the current tang for 1-2 days while in quarantine. Also for what it's worth, I used to have a school of 5 Paracanthurus in this aquarium that were perfectly healthy for as long as I had them, but that was before the initial outbreak.

Three fish, 2 clowns (asymptomatic) and 1 damsel (symptomatic) all at least 15 years old, were present in the aquarium when I introduced the new tang, mandarin, and dottyback this year.

Cheers, Peter

 

[Jay Hemdal]

Well, the fish you listed are clearly demarcated between species known to show HLLE and those that don’t. The number is pretty small, but there does seem to be clear correlation for HLLE here.
Jay

 

[Christopher Aslett]

Stop using granular activated carbon (GCA). Continuous use is incongruous. After 48 hours it begins to leach the bad stuff it has absorbed back out into the water. The long term use of GAC is moot point. It should be used for 48 hour periods very infrequently. Once very month and a half It should be washed beforehand in copious amounts of R/O water. It's the dust that causes HLLE. I wouldn't rule out other things going on with your water and system, however, the carbon is the first thing to address.

 

[Peter Houde]

Stop using granular activated carbon (GCA). Continuous use is incongruous. After 48 hours it begins to leach the bad stuff it has absorbed back out into the water. The long term use of GAC is moot point. It should be used for 48 hour periods very infrequently. Once very month and a half It should be washed beforehand in copious amounts of R/O water. It's the dust that causes HLLE. I wouldn't rule out other things going on with your water and system, however, the carbon is the first thing to address.

Thanks. I'm inclined to agree about carbon, at least that it is unnecessary. Macroalgae alone was enough to reduce nitrogen level to undetectable (NYOS test). Phosphates are altogether another story. I did get myself a phosphate reactor but I haven't hooked it up yet.

If after reading my water parameters at the top of this thread you have any additional suggestions about what other things might be going on with my water system then I'm all ears.

Cheers

 

[Christopher Aslett]

Thanks. I'm inclined to agree about carbon, at least that it is unnecessary. Macroalgae alone was enough to reduce nitrogen level to undetectable (NYOS test). Phosphates are altogether another story. I did get myself a phosphate reactor but I haven't hooked it up yet.

If after reading my water parameters at the top of this thread you have any additional suggestions about what other things might be going on with my water system then I'm all ears.

Cheers

Hi, From one photograph it looks like you might have eutrophication. High nutrients, possibly phosphate. Check your R/O water and salt mix for phosphate. Both reservoirs need continuous aeration to prevent the biological generation hydrogen sulphide (H2S). Discard water that has not been aerated for 24 hours. Your fish appear to be swimming in low ORP water which my be a sign of H2S or carbon dioxide retention.

Amongst other things marine, I used to be a marine consultant so yes I could help you however, to be of most benefit I'd require detailed images of the entire system and reservoirs including a description of your husbandry practices . PM me, Chris

 

[Peter Houde]

Hi, From one photograph it looks like you might have eutrophication. High nutrients, possibly phosphate. Check your R/O water and salt mix for phosphate. Both reservoirs need continuous aeration to prevent the biological generation hydrogen sulphide (H2S). Discard water that has not been aerated for 24 hours. Your fish appear to be swimming in low ORP water which my be a sign of H2S or carbon dioxide retention.

Amongst other things marine, I used to be a marine consultant so yes I could help you however, to be of most benefit I'd require detailed images of the entire system and reservoirs including a description of your husbandry practices . PM me, Chris

Dear Chris,
I guess I just can't figure out how to use conversations. I tried to send you a message directly as a new conversation, but now I can't figure out how to navigate to conversations to see if you responded. I don't even know how I managed to create a conversation in the first place. Sorry.
Cheers, Peter

 

[Christopher Aslett]

Dear Chris,
I guess I just can't figure out how to use conversations. I tried to send you a message directly as a new conversation, but now I can't figure out how to navigate to conversations to see if you responded. I don't even know how I managed to create a conversation in the first place. Sorry.
Cheers, Peter

Peter, Once you're singed at the top of the page next to to your avatar and the word account, there is an icon of an envelope. All your private conversation/messages can be found there.

I been confused and replied to your conversation rather than the thread. They look the same. The conversation is also called pale-face disease.

 

[Christopher Aslett]

Below is what I sent to Peter in error. Perhaps it will benefit someone.

One thing I have gathered is that you are very hands-on hobbyists. Those types do not fare well as hands in and on, usually creates instability to which these animals are unaccustomed. Slowly does it.

Start at the most fundamental part of the system. The source of water. R/O must come from a unit that is never stopped. They must run continuously. Anyone that has dismantled one knows it's slimy with a biofilm. Even on the “clean” side of the membrane. What we learn from this is that R/O is not sterile. It has bacteria in it. If the water is not supplied with air in the form of large air bubbles from the movement of production, or the unit is stopped, the water diminishes in dissolved oxygen, becomes stagnant and some of those bacteria begin to produce hydrogen sulphide. Water in mains tap water does not go stagnant because the water companies put chloramine in it as a sanitiser. It is an oxidant that prevents the dissolved oxygen concentrations from plummeting. R/O does not have chloramine it is so can attain zero dissolved oxygen within 24 hours of being stuck in pipework. That includes any water in your system in complicated pipework. That includes the deadly practice of using undrilled pipework for reef supports. An error even well-respected microbiologists get very wrong.

H2S is highly toxic in tiny, tiny quantities. The same thing occurs within deep substrate (sand beds). If they are disturbed, then the chances are they will release hydrogen sulphide into the water. If not directly, in the water that is syphoned. If this water is filtered and put back into the aquarium, it will be toxic and destabilise the pH long term. This will cause chronic if not acute stress to your fish and livestock. Worst case scenario is immediate or eventual mortality. H2S is a powerful reductant that causes the water to look grey/milky. That is what I saw on those images of your fish… Water with an optimal ORP of 370 mV will be bright, gin clear, and sparkly. The best ORP meter is your eyes as the hobbyists ORP meters are very inaccurate and thus should never be used to regulate any equipment. TMC sells accurate commercial ORP monitoring and control equipment, however, it will set you back 2,500GBP. That is a wholesale price. I wrote an article for Marine World Magazine many moons ago discussing how to measure ORP by sight. There might be a copy somewhere.

Salt mix requires large air bubbles to acquire CO2 and its buffering. 48 hours minimum.

PH instability can contribute to the persistence of unsightly microalgae. Macroalgae are a good thing, even Valonia species (bubble). I like it. You appear to be battling a dinoflagellate or "brown algae" bloom. 0.045 milligrams per litre of phosphate is about right. No lower. Your concentration is currently 10 times the optimal. Stopping R/O units also lets “dirty” water flood onto the “clean” side of the membrane. That includes phosphate. 1 milligram per litre (ppm) of phosphate in most mains water to sequester lead and copper.

The above is a good place to start. Stop disturbing the sand bed – if you are - and get your source water right. To raise the ORP of your system, buy two lengths of 20-inch 5 mm OD clear acrylic tubing from eBay and pump two streams of 1 cm sized air bubbles in the corners of the aquarium. No smaller. Do not use an air stone. No larger or vigorous. A tiny amount from an average air pump. Microbubbles are to be discouraged. If you have poisoned the system with H2S recently it will take around two weeks for that water to recover.

Do you have a sump? Please advise. I’d also advise other changes but need some more info first. All the above is guess work. I like to deal with certainties. If it does not apply or help you, it might help someone else.

 

[Peter Houde]

Well, the fish you listed are clearly demarcated between species known to show HLLE and those that don’t. The number is pretty small, but there does seem to be clear correlation for HLLE here.
Jay

Dear Jay,

I suspect the facial discoloration is indeed HLLE and I'm resigned to its being permanent scarring. But that's not consistent with fin erosion, is it? Fin erosion of the Paracanthurus is continuing even though the fish has been in a bare quarantine tank for 52 days (no carbon; 30% water changes every other day). The tang's fin erosion is most noticable on the caudal fin and proceeding from the distal margin proximally. Fin damage on the damselfish seems more likely to have been inflicted by tank mates. It looked more like tatters and it has healed considerably since the fish has been being quarantined, rather than progressing as in the tang.

I'm willing to give this one last shot before giving up and returning the tang and damselfish back to the display aquarium. You previously wrote "My general recommendation is that if you try a full antibiotic treatment with no results, the issue either isn't bacterial, or you need to try a different antibiotic." Can you recommend one, anything at all? Maybe a topical application? (For reference, already tried to date: food treated with metranidazole and nitrofurantoin; 5 min freshwater dip, extended hyposalinity, 5 successive weekly treatments of 2.5 mg/l praziquantel, 2 weeks 5mg/l copper sulfate, and 5 day nitrofurazone treatment, 10 min Hydroplex dip followed by 2 hour diluted treatment on 5 consecutive days according to directions.)

Thanks in advance, one last time.

Cheers, Peter

 

[Jay Hemdal]

I'm not a big fan of any topical meds for marine fish, I don't think they work, most just rinse off.

Here is a hypothesis; the root cause of the fin degradation is HLLE, but the open tissue can become infected, leading to more rapid fin erosion. In my HLLE study from back in 2011, we used ocean surgeonfish and induced HLLE in them with carbon. We didn't see fin erosion (that species isn't prone to it like yellow tangs and hepatus are). However, the skin erosion, when we sent samples out for histopathology, came back as infected with bacteria. So - my thought all these years that HLLE lesions were basically sterile, was not borne out by the pathology.

Do you think you could get access to Enrofloxacin (Baytril)? If so, you could try a 2 ppm dose, with a 50% water change each day, redosing with a 1 ppm dose after each change....for 3 days.

Easier to get would be Neoplex (Neomycin sulfate) Seachem makes that. Dose according to the label directions.

Jay

 

[Peter Houde]

I'm not a big fan of any topical meds for marine fish, I don't think they work, most just rinse off.

Here is a hypothesis; the root cause of the fin degradation is HLLE, but the open tissue can become infected, leading to more rapid fin erosion. In my HLLE study from back in 2011, we used ocean surgeonfish and induced HLLE in them with carbon. We didn't see fin erosion (that species isn't prone to it like yellow tangs and hepatus are). However, the skin erosion, when we sent samples out for histopathology, came back as infected with bacteria. So - my thought all these years that HLLE lesions were basically sterile, was not borne out by the pathology.

Do you think you could get access to Enrofloxacin (Baytril)? If so, you could try a 2 ppm dose, with a 50% water change each day, redosing with a 1 ppm dose after each change....for 3 days.

Easier to get would be Neoplex (Neomycin sulfate) Seachem makes that. Dose according to the label directions.

Jay

Thanks so much again for the speedy reply and advice. I might be able to get enrofloxacin by ordering through the university or perhaps from a local veterinarian. To be sure I don't misunderstand, the 1ppm re-dosing on successive days is based on the total tank volume in order to maintain the original concentration, not just 1 ppm to the changed water, right? Cheers, Peter

 

[Jay Hemdal]

Thanks so much again for the speedy reply and advice. I might be able to get enrofloxacin by ordering through the university or perhaps from a local veterinarian. To be sure I don't misunderstand, the 1ppm re-dosing on successive days is based on the total tank volume in order to maintain the original concentration, not just 1 ppm to the changed water, right? Cheers, Peter

Yes, that’s correct, just replacing he meds lost due to the water change. Also, I can’t tell you what issues you might have dosing this outside of a treatment tank. Also, enrofloxicin often has binders in it, so you need to dose for the active component only.
Jay

 

[Peter Houde]

Yes, that’s correct, just replacing he meds lost due to the water change. Also, I can’t tell you what issues you might have dosing this outside of a treatment tank. Also, enrofloxicin often has binders in it, so you need to dose for the active component only.
Jay

Dear Jay,
I finally just got the enrofloxacin. The fish is already in a quarantine tank that has already been turned over, so there are already bacteria. Do I want to restart the quarantine tank with 100% new water, no 'starter' bacteria, and no filter pad? Or is it OK to simply bring the concentration up to the initial 200 ppm by way of a partial water change and leave the filter pad (fibrous, but no carbon) in there? In other words, are existing nitrifying bacteria going to 'saturate' the antibiotic?
Cheers, Peter