Formalin

Humblefish

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FORMALIN
Formalin (37% formaldehyde)

What It Treats Marine Velvet Disease (Amyloodinium), Brooklynella, Uronema, Flukes (Monogeneans), Black Ich (Turbellarians).

How To TreatIn order for Formalin to be fully effective, the product you are using should contain 37% formaldehyde. At present time there is only one aquarium product which meets this criteria: Parasite-S (MSDS is here) from Syndel USA: https://www.syndel.com/parasite-s.html

You can also use 37% UPC lab grade Formaldehyde (Amazon sells it - also contains 14-15% Methanol which is OK), following these dosing instructions:

When using 37% formaldehyde dosages are as follows for marine environments above 70°F (otherwise follow directions on the product’s label):
1) In-tank treatment: 1 milliliter (ml) per 10 gallons, or 2 drops per gallon daily in a bare aquarium.

2) 30-45 minute bath treatment: 0.6 ml per gallon, or 12 drops per gallon. Aerate vigorously and treat at this concentration for no more than 45 minutes.

These are other products which contain formaldehyde (e.g. Quick Cure, Aquarium Solutions Ich-X, Kordon Rid-Ich Plus), but because these contain less than 37% formaldehyde their effectiveness is difficult to predict.

Formalin is best administered in a bath solution for 30-45 minutes. The bath is best done in a large glass bowl or container, but a plastic bucket is fine as well. (However, keep in mind that plastic may absorb some of the medication and then leach it back out during future use.)

Temperature/pH/salinity of the bath water should match the tank the fish is coming from (and going into afterwards.) It is very important to heavily aerate the bath for at least 30 minutes before and also during treatment to compensate for oxygen depletion. The fish should be placed in a premixed bath solution. DO NOT add more formalin after the fish is already in the bath.

It is important to always transfer the fish into a new/sterile quarantine tank (QT) post bath. Returning the fish to the same tank you took him out of will just result in reinfection. It is also impossible to determine if just one formalin bath will result in 100% eradication of the pathogen you are trying to eliminate. Therefore, it is wise to do follow-up treatment in a QT:

1) Velvet: Copper or Chloroquine phosphate for 30 days.
2) Brook & Uronema: Metronidazole (e.g. Seachem Metroplex) or Chloroquine phosphate for 14 days.

3) Flukes & Black Ich: Prazipro or another formalin bath 5-7 days later.

It is also possible to achieve 100% eradication with repeat formalin baths, but it’s important to give the fish 48 hours to recuperate in-between baths. Post bath, always transfer the fish into a new/sterile QT to prevent reinfection. And observe closely for at least 30 days to be sure the fish is 100% disease-free.

You can dose formalin directly into a quarantine tank, but this can be risky due to the harshness of formalin and how quickly it can deplete the water of oxygen. Providing additional gas exchange to the QT is a must! This can be accomplished by using an air stone or pointing a powerhead towards the surface of the water. (Anything that causes ripples at the surface.) A fish being treated must be monitored closely and should be removed if showing signs of distress – this applies when treating in QT or in the bath solution.

ProsTreats or provides temporary relief for a wide range of diseases. In some cases, formalin can “buy you more time” until a proper treatment can be done.

Cons/Side EffectsFormaldehyde is a known carcinogen. Therefore, precautions must be taken when using it. Preventing your skin from coming in contact with it by wearing waterproof gloves and not breathing in any fumes by wearing a face mask is highly recommended. Formalin also can be harsh on the fish’s gills and will quickly deplete oxygen from the water. DO NOT USE if a fish has open wounds. There is anecdotal evidence (but never scientifically proven) that some fish exposed to formalin don’t live past 18-24 months. In some areas, the purchase of formalin is prohibited.

Further reading on using formalin to control fish parasites: http://fisheries.tamu.edu/files/2013/09/Use-of-Formalin-to-Control-Fish-Parasites.pdf
 
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evmibo

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My bottle of Kordon Rid Ich Plus contains "4.26% formaldehyde (11.52% formalin) and zinc-free chloride salt of malachite green." Is this too weak?

One more question, just to clarify. The bath should be done in more freshwater (post freshwater dip) or water of the same salinity as the QT the fish will be going into?
 

melypr1985

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My bottle of Kordon Rid Ich Plus contains "4.26% formaldehyde (11.52% formalin) and zinc-free chloride salt of malachite green." Is this too weak?

One more question, just to clarify. The bath should be done in more freshwater (post freshwater dip) or water of the same salinity as the QT the fish will be going into?
12% is pretty weak. I would find one of the products mentioned above as they will have the right concentration. You'll do the dip in the same salinity as the QT.
 

stevo01

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Formalin converts into formic acid and formic acid can have some interesting negative side effects. I "think" fish blindness could be one of these side effects, but i cant find any research thats been done on this. Just results on humans/and some test animals.

Ruby Reef Rally contains a very small ammount and I have not witnessed any negative effects from using this small ammount.

Quoted from their web site.

"RALLY ™'s safety and effectiveness has been widely proven in hobby and commercial applications. The reagents in RALLY ™ are blended by a proprietary method that renders RALLY ™ much more effective than the sum of its parts -- i.e., acriflavine + aminoacridine + an activator (miniscule amount of formalin) -- for the control of external parasites and bacterial fin and tail rot."
 

thirst

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If I set up a clean qt tank. Then catch my fish and display tank, dip them in formalin, then put in qt tank.

Would this get rid of all the brook? If it doesn't, and I dip the dip again in 48 hours, do I need to set up a second qt?
 
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Humblefish

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If I set up a clean qt tank. Then catch my fish and display tank, dip them in formalin, then put in qt tank.

Would this get rid of all the brook? If it doesn't, and I dip the dip again in 48 hours, do I need to set up a second qt?
In most cases, brook can be eradicated after just one 45 min formalin bath. Provided the fish is then transferred into a clean, sterile QT (nothing reused from the DT).

However, I like to dose metronidazole (ex. Metroplex, Metro-MS) into the QT just to play it safe. Treat for 10 days.
 

jtl

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Resurrecting this thread. Is it a good idea to dose Formalin after my last ttm transfer? I have already dosed Prazipro on transer 2 and it is currently in transfer 4 (my last transfer). This is all being done prophylactically, the fish have no signs of disease, but I don't want it introduce anything into my DT, but I also do not want to harm the fish. I have a wrasse, a firefish and a midas goby.
 

evmibo

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iirc and without reading through this thread again, Formalin seems to be a last resort type of treatment. I seem to remember a couple experts on here mentioning that fish will often die of what is thought to be cancer 1-3 years after being treated with Formalin as well (carcinogen). Ever since I lost 80% of my fish to either brook or velvet (still not really sure), I now treat with prazipro treatments,, then 28 days of copper before DT. Just my two cents hope it works out for you.
 

jtl

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None of these treatments are good from what I have read. I never used to even bother with treatments or qt. Doing it a little different after recently losing two fish to flukes. After this last ttm transfer it is either formalin and then the DT or straight to the DT. I don't want to use copper. I know a lot of people use formalin for a "bath" and they claim with no problems but who knows about long term. I did the prazipro already but that won't help with brook or velvet from what I understand. The ttm is pretty well accepted as a treatment for ich but it is a lot of work. Do you know Ron "Reefman" Lindensmith? He is a long term reefer and lives in Cape Coral.
 

evmibo

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Yeah you just have to do what works best for you and your fish. I lost 5 of 7 fish in one week. From there on out QT, prazipro, freshwater dip/bath, and copper... Healthiest fish I've ever had. Way more work but a clean DT is worth it!!! Yes I know Ron, I haven't been affiliated with the club for a couple years though as I don't have as much interest in the club aspect anymore.
 

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My story isn't much different from most of the other posts on every forum everywhere else. Never really took the time or expense to QT/Treat any of the additions to my tank until recently. And TBH I've never really had any catastrophic issues until recently. After setting up my newest tank in the new place I added a few fish and everything seemed to be moving right along just as I had always dreamed (slow and steady) 5 or 6 fish already in the DT and everything was good.......unnnnnnntil I decided I really wanted a Powder Brown tang that I saw at my LFS. Which ultimately introduced ICH and now my tank has been fallow for no less than a month and a half because every single fish died before I could get a chance to pull them all out. I decided to build a sweet hospital treatment tank (complete with Chiller, Sump, ATO, and Skimmer) to treat and observe EVERY SINGLE THING THAT WILL EVER BE GOING IN MY TANK FROM NOW ON!

With that being said, I've read a hundred threads and all the related posts until my brain hurt. But I'm still a little unclear about a few things. Does anyone prophylactically treat for Brook in clownfish or should that solely be used as a reactive treatment. I plan to pick up a couple black mis-barred clowns later on to be added in a couple months after the Powder Blue, Vanderbilt Chromis' and the Melanurus Wrasse that I currently have in the QT are treated and settle in to the DT. So here's the plan if in fact anyone DOES "pre-treat" Formalin for Brook, please feel free to redirect me if I seem too far off. (@Humblefish )

Drip Acclimation

(45 min formalin bath-clowns only)

Into Hospital/Observation tank

48 hrs observation

48 hr Prazipro

25% WC / 5 day observation

2nd 48 hr Prazipro

25% WC + carbon / 5 day observation

30 day Cuprion Ionic Copper Treatment

14 day Cuprisorb & Poly-Filter / Observation

Transfer to DT

from all that I gathered that should cover most (if not all) parasitic worms, ICH, and Velvet. Does that seem reasonable? I just really want to have a healthy environment and happy fish.








 

jtl

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As you have likely found out there are numerous opinions. I did the ttm with prazipro on the 2nd and 4th water change than before they went into the DT I did a formalin dip for 45 minutes. Everything went well, they ate throughout the process. Notice that I did not do an observation period in a QT because I figured I observed the fish for 12 days and saw nothing unusual. I got serious about treating incoming fish after losing two to flukes, something I have never encountered before. Interestingly my pair of clowns did not exhibit symptoms but I did two full treatments of prazipro in my DT to be safe. The two fish that had flukes were purchased from my lfs but they did not show signs of flukes for 2 months. I did not treat them for anything because the owner of the store claimed he had them under observation for 3 weeks. Right or wrong I never worried about my clowns. They came from a large wholesaler and are captive breed by a couple of marine biologists. I figured that would be all over any disease in their facility.
 

jtl

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As you have likely found out there are numerous opinions. I did the ttm with prazipro on the 2nd and 4th water change than before they went into the DT I did a formalin dip for 45 minutes. Everything went well, they ate throughout the process. Notice that I did not do an observation period in a QT because I figured I observed the fish for 12 days and saw nothing unusual. I got serious about treating incoming fish after losing two to flukes, something I have never encountered before. Interestingly my pair of clowns did not exhibit symptoms but I did two full treatments of prazipro in my DT to be safe. The two fish that had flukes were purchased from my lfs but they did not show signs of flukes for 2 months. I did not treat them for anything because the owner of the store claimed he had them under observation for 3 weeks. Right or wrong I never worried about my clowns. They came from a large wholesaler and are captive breed by a couple of marine biologists. I figured that would be all over any disease in their facility.
 
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Humblefish

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With that being said, I've read a hundred threads and all the related posts until my brain hurt. But I'm still a little unclear about a few things. Does anyone prophylactically treat for Brook in clownfish or should that solely be used as a reactive treatment. I plan to pick up a couple black mis-barred clowns later on to be added in a couple months after the Powder Blue, Vanderbilt Chromis' and the Melanurus Wrasse that I currently have in the QT are treated and settle in to the DT. So here's the plan if in fact anyone DOES "pre-treat" Formalin for Brook, please feel free to redirect me if I seem too far off. (@Humblefish )
I recommend treating for brook with clownfish, but metro is a better choice for prophylaxis use: https://www.reef2reef.com/threads/metronidazole.298762/

IMO; formalin is best reserved for emergency situations where an active infection of brook has been spotted.
 

sensei

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Humble,

do you know if there are fish sensitive to formaline?
or it can done to any fish?

I am thinking of doing a formalin dip at the end of each TTM.
can it be mixed with prazi? I ask because I usually do Prazi on 2nd and 4th TTM
and If I do formalin in each TTM, the water of the 2nd and 4th would have prazi.

thanks
 
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Humblefish

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@sensei I would never use formalin on any scaleless fish (same as copper). All other fish are going to be hit or miss. You can give one Yellow Tang a formalin bath and he does fine with it; the next one will have an adverse reaction and struggle in it. o_O

I wouldn't mix formalin with Prazipro due to the risk of a bacterial bloom occurring.
 

sensei

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Humble,
Thanks for your answer

I just had an insident were all fish died due to velvet that showed 7 weeks after qt, only a puffer survived.
Before I just did TTM , 2 prazi shoots and 1 formalin dip
I am thinking of modifying my qt protocol as follows:

4 Tank Transffer Method 3 days each
Formalin at the end of 1st and 3th TTM
Prazi on second day of 2nd and 4th TTM
after TTM observation of 30 days in CP at a concentration of 40mg/g

What do you think? any recomendations?
Thanks again
 
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Humblefish

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Humble,
Thanks for your answer

I just had an insident were all fish died due to velvet that showed 7 weeks after qt, only a puffer survived.
Before I just did TTM , 2 prazi shoots and 1 formalin dip
I am thinking of modifying my qt protocol as follows:

4 Tank Transffer Method 3 days each
Formalin at the end of 1st and 3th TTM
Prazi on second day of 2nd and 4th TTM
after TTM observation of 30 days in CP at a concentration of 40mg/g

What do you think? any recomendations?
Thanks again
Some peers of mine have claimed success using formalin to treat velvet at the end of TTM, just as you are describing. They perform a 45 min formalin bath at the tail end of transfers 1 & 3. While it is certainly possible to eradicate velvet this way, I'll have to see it for myself in order to believe it. ;)

I'm also keen to give this a go for treating velvet without chemicals: https://www.reef2reef.com/threads/tank-transfer-method.192655/page-11#post-3549495
 

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