Formalin Treatments***Help***

Dear Kris:

If used according to the instructions, formalin is very effective in treating a very wide range of ectoparasites, including the eye looks that sometimes caused Popeye or exophthalmia, and is a very good medication to use for this type of problem. But it is serious stuff – dangerous stuff – and it’s very important to follow the directions to the letter, because formalin is not a safe medication to overdose and because it depletes the oxygen in the water very quickly. It’s very important to keep the treatment container well aerated throughout the treatment period and to limit the baths to no more than 30 minutes, if possible, sir.

This is what I normally advise home hobbyists regarding the use of formalin, Kris:

Formalin Baths

Formalin (HCHO) is basically a 37% solution of formaldehyde and water. It is a potent external fungicide, external protozoacide, and antiparasitic, and is thus an effective medication for eradicating external parasites, treating fungal lesions, and reducing the swelling from such infections. It is a wonder drug for treating cases of Popeye caused by trematodes, and also eradicates external nematodes.

In my experience, provided it is administered properly, seahorses tolerate treatment with formalin very well at therapeutic dosages. For a long term bath the correct dose is 15 to 25 mg/L. [Note: 25 mg/L equals 1 ml (cc) of 37% formalin per 10 gallons of water.] This is done every other day for 3 treatments.

For a short term bath (dip) the correct dose is 250 mg/L. This would equal 1 ml (cc) of 37% formalin per 1 gallon of water. This should be for about 45 minutes to 1 hour. In my opinion, formalin is a safe, effective treatment for parasitic infections in seahorses providing you don’t exceed these dosages and observe the following precautions for administering the medication properly:

Many commercial formalin products are readily available to hobbyists, such as Kordon’s Formalin 3, Formalin-F sold by Natchez Animal Supply, and Paracide-F, sold by Argent go to top Chemical Laboratories. Or whatever brand of formalin is available at your fish store should work fine, Pam.

A formalin bath simply involves immersing the seahorse in a container of saltwater which contains the proper dosage of formalin for a period of 30-60 minutes before transferring it to your hospital tank. Include a hitching post of some sort in the container and follow these instructions: place the fish in a three-gallon bucket or a similar clean, inert container containing precisely one gallon of siphoned, aerated tank water. Medicate the bucket of water with with the appropriate amount of formalin for a concentrated bath according to the directions on the label. Place an airstone in the bucket and leave the fish in the bath for 30 minutes. If at any time the fish becomes listless, exhausted or loses its balance, immediately place the fish in clean, untreated water in your hospital tank.

I want you to be aware of these precautions when administering the formalin bath:
Formalin has limited shelf life and degrades to the highly toxic substance paraformaldehyde (identified as a white precipitate on the bottom of the solution); avoid using any formalin product which has such a precipitate at the bottom of the bottle.
Formalin basically consumes oxygen so vigorous aeration must be provided during treatment.
Time the bath closely and never exceed one hour of chemical exposure at this concentration.
Observe the seahorse closely during the bath at all times, and it show signs of distress before the allotted time has elapsed, remove it from the treatment immediately.

If you can obtain Formalin 3 from Kordon at your LFS, Kris, these are the instructions you should follow for your formalin dip:

METHOD 2 (DIP) FOR THE PREVENTION OR TREATMENT OF FISH DISEASES
(a) To a clean, non-metallic container (i.e., a plastic bucket), add one or more gallons of fresh tap water treated with Kordon’s AmQuel . For marine fish use freshly prepared saltwater adjusted to the same specific gravity (or salinity) as in the original tank. Make sure the temperature in the container is identical to that in the aquarium
(b) Add 1 teaspoons of Formalin·3. This produces a concentration of 100 ppm. formaldehyde.
(c) Agitate the solution with an airstone and adjust for a moderately strong flow of air.
(d) Remove the fishes to be treated and deposit them in the container for a treatment period of not more than 50 minutes. Immediately after the treatment period, or if signs of distress are noted, remove the fishes to a previously prepared recovery tank. The fishes may be returned to their original tank, but the presence of the original disease-causing agents in the tank water may result in a reoccurrence of the disease condition.
(e) Observe recovering fishes. Make sure that tankmates do not molest them during recovery.
(f) Repeat treatment as needed, every week. Each treatment is very stressful to the treated fishes. Do not reuse the dip solution.

For additional information on treating fishes with Formalin 3 by Kordon, see the following web page:

Click here: KPD-54 Formalin-3
http://www.novalek.com/kpd54.htm

If you get another brand of formalin, just follow the instructions that it comes with for a concentrated bath or dip (not prolonged immersion or a long-term bath) or follow the following directions, courtesy of Ann at the org:

FORMALIN Short-Term BATH Dosage and Preparation Instructions
Active Ingredient: 37% Formaldehyde
Indication: external parasites
Brand Names: Formalin, Formalin-MS
Notes:
1. Do NOT use Formalin that has a white residue at the bottom of the bottle. White residue
indicates the presence of Paraformaldehyde which is very toxic.
2. “Formalin 3” by Kordon contains only 3% Formaldehyde. Dosing instructions will need to be modified if using this product.
• Fill a small tank with aged, aerated, dechlorinated marine water. Match the pH, temperature, and salinity to that of the tank the Seahorse is currently in.
• Add an artifical hitch and 1-2 vigorously bubbling airlines. Formalin reduces dissolved O2 so heavy aeration is required.
• Add 1ml/cc of Formalin per one gallon (3.8 liters) of tank water. Allow several minutes for the Formalin to disperse.
• Place the Seahorse into the dip water for 45-60 minutes unless it is showing signs of an adverse reaction. If the Seahorse cannot tolerate the Formalin dip, immediately move it back to the hospital tank.
• Observe the Seahorse for 24hrs for signs of improvement.

Okay, Kris, that’s the quick rundown on treating seahorses with formalin, either as a bath or via prolonged immersion in a hospital tank. If used properly, formalin is safe and effective in treating ectoparasites of most every kind, but you must use it carefully according to instructions and be sure to keep the treatment container well aerated, or you can overdose the seahorses or lose them to asphyxiation because of insufficient dissolved oxygen in the treatment container.

If you can obtain the Formalin 3 by Kordon, Kris, here is some more detailed information on how to use it properly and the types of problems it is helpful in treating:

Kordon Formalin 3 treatment instructions

Formalin can be useful in treating fish with the following clinical symptoms:

Increased respiration; loss of normal body color; presence of discrete white spots (freshwater or saltwater “ich”); white areas on the body with circumscribed, reddish perimeter (Epistylis and/or bacterial infection); scratching on tank bottom or objects, lethargy, white cottony tufts or strands on body (fungus); dust-like, “peppered”, yellowish spots on body surface (Oodinium); whitish skin slime or filmy body covering or patches (columnaris disease); disintegrating fins or fin edges (fin rot); mouth “fungus” (bacterial infection); pustules, furuncules or ulcers.

If any of the above symptoms are similar to the problems you’ve noticed with your seahorses upon close inspection, then administering formalin baths to the seahorses may be helpful, mermaid. Formalin 3 by Kordon is the medication I prefer for these treatments. These are the instructions for treating fish with Formalin 3, the Kordon brand of formalin, which is readily available at most fish stores:

SUGGESTED TREATMENT PROCEDURES

The following procedures are suggested for both freshwater and marine systems, unless otherwise noted. It is important to note that some activated carbons can remove formaldehyde from water, but formaldehyde persists for only a few hours in aquariums and does not accumulate in the water.

SUCCESSFUL DISEASE TREATMENT

Successful treatment of diseases of aquarium fishes relies upon several factors. Firstly, as discussed above (“General Diagnosis of parasitic Diseases of Fishes”), a proper diagnosis of the disease must be made, and this can be one of the most difficult tasks facing an aquarist.
Secondly, the start and duration of a treatment is important. A disease which will usually respond to a given medication may not respond if the treatment is started too late, or if the length of treatment is not long enough.

Lastly, the correct medication at the correct dosage must be used with the proper treatment method. Formalin·3, for instance, will not be effective against systemic (internal) diseases of aquarium fishes because the therapeutic effects of the formaldehyde are restricted to those surfaces of the fishes that contact the treated water.

Water changes are another important factor. Some medications state that water changes are not necessary, but the fact is that water changes are always helpful. Depleted dissolved oxygen levels are replenished, dissolved organics are removed as are free-living disease organisms.

Treatment in a separate treatment or hospital tank, if possible, is also important. However, this is often a nuisance and in many cases the entire aquarium population is diseased.

TREATMENT OF FUNGAL AND PROTOZOAL DISEASES OF FISH (LONG-TERM BATH)

(a) Since there is conflicting evidence regarding the safety of formaldehyde to biological (nitrifying) filtration, all long-term bath treatments with Formalin·3 may (at the user’s discretion) be done in a separate hospital or treatment tank.
(b) Remove granular activated carbon from all filters used on the treatment tank; clean or change the mechanical filter media (i.e., filter floss), and return the filter(s) to service (minus the carbon).
(c)Make a partial water change of approximately 25%
(d) Depending upon the condition of the fishes needing treatment (i.e., the severity of the disease, involvement of the gills and the degree of debilitation), the dosage should be varied from 1 to 2 teaspoons per 10 gallons (10 to 20 ppm.) Severely diseased or debilitated fishes should be treated at the lower dosage.
(e) The treatment may be repeated every 24 hours, by repeating all of the above steps, including the required water changes.
(f) The dosage may be increased as the condition of the fishes being treated improves.
(g) If the fishes were removed to a separate tank, the original aquarium or pond should remain devoid of all fishes for a period of at least 4 days to insure all of the remaining infestation has expired.

METHOD 2 (DIP) FOR THE PREVENTION OR TREATMENT OF FISH DISEASES

(a) To a clean, non-metallic container (i.e., a plastic bucket), add one or more gallons of fresh tap water treated with Kordon’s AmQuel . For marine fish use freshly prepared saltwater adjusted to the same specific gravity (or salinity) as in the original tank. Make sure the temperature in the container is identical to that in the aquarium
(b) Add 1 to 2 teaspoons of Formalin·3. This produces a concentration of 100 to 200 ppm. formaldehyde.
(c) Agitate the solution with an airstone and adjust for a moderately strong flow of air.
(d) Remove the fishes to be treated and deposit them in the container for a treatment period of not more than 50 minutes. Immediately after the treatment period, or if signs of distress are noted, remove the fishes to a previously prepared recovery tank. The fishes may be returned to their original tank, but the presence of the original disease-causing agents in the tank water may result in a reoccurrence of the disease condition.
(e) Observe recovering fishes. Make sure that tankmates do not molest them during recovery.
(f) Repeat treatment as needed, every week. Each treatment is very stressful to the treated fishes. Do not reuse the dip solution.

If you are going to use the formalin to treat your seahorses, Kris, please copy the following URL and paste it in your web browser. It will take you to a webpage with additional information about Formalin 3, and you should read through the information there before you begin the treatments:

http://www.novalek.com/kordon/formalin/index.htm

When used properly, formalin should not cause loss of appetite, Kris.

Judging from your description, it sounds like your seahorse is suffering from snout rot and the initial stages of tail rot in addition to her I problems, sir. You will need long-term antibiotic therapy to resolve the snow problem and tail problem, so do a search on this form for “tail rot” and adjust your treatment regimen accordingly.

Good luck!

Respectfully,
Pete Giwojna, Ocean Rider Tech Support

Dear Kris:

You’re very welcome, sir – if the information regarding the formalin was too late to help in your case, at least it’s posted on the discussion forum now and will hopefully be able to help other hobbyists seahorses in the future.

The excited “trumpeting” behavior you observed from your stallion when he was reunited with the female is a courtship display, more specifically an invitation and a prelude to the copulatory rise and exchange of eggs. It seems that absence only makes the heart ponder in the case of our amazing aquatic equines, and that your stud is ready to consummate their pair bond immediately. Having a healthy interest in courtship and breeding is always a good sign, sir, so hopefully things are looking up.

If the ammonia spike was not pronounced or prolonged, and you detected it early and added more nitrifying bacteria as soon as possible, then I don’t think it should have any further deleterious affects on the seahorses. If they are interested in mating at this time, and your ammonia, nitrite, and nitrate levels are all back to normal again, and optimum water quality has been restored, I think the ponies should be fine despite the transitory ammonia spike.

I always like to keep SeaChem Stability on hand so that I can add a dose of it following every partial water change, whenever I have used any medications in the aquarium, whenever there is a blip in the ammonia or nitrite levels, as well as using it routinely for monthly “boosters” to assure that the biofiltration is operating at maximum efficiency at all times. The Stability by SeaChem includes not only beneficial nitrifying bacteria that convert ammonia and nitrites and then reduce the nitrates to nitrates, but also has denitrifying bacteria that complete the nitrogen cycle by converting nitrates to nitrogen gas, as well as facultative bacteria that help to break down detritus and any other gunk of organic origin that accumulates in the substrate or filter media, and is therefore extremely useful for helping to maintain optimum water quality at all times

Best wishes with all your fishes, Kris!

Respectfully,
Pete Giwojna, Ocean Rider Tech Support

Dear Kris:

Unfortunately, it sounds like you may be experiencing an outbreak of hydroids, sir. The tiny little jellyfish are the mobile Medusa (technically hydromedusae) form of the hydroids. Most hobbyists simply refer to these guys as “snowflake hydroids” and, like all cnidarians, they are capable of stinging. There are very many types of hydroids, but the snowflake hydromedusae are typically armed with very potent nematocysts their capable of delivering a nasty sting. In fact, many hobbyists first become aware of them when they receive stings to their hands or arms well performing maintenance in the aquarium.

Sooner or later hydroids will appear in any marine aquarium that is receiving regular feedings of rotifers, copepods, or baby brine shrimp or plankton suitable for filter feeding invertebrates. It’s inevitable because they can gain entry into the aquarium in many ways. For example, they are notorious hitchhikers. Both the colonial polyp stage and the free-swimming micro-jellies can thumb a ride on live rock, macroalgae, hitching posts, sand or gravel, specimens of all kinds, or within so much as a single drop of natural seawater (Abbott, 2003). Beware of fuzzy looking seashells! Very often hydrozoans come in on the shells of the hermit crabs or snails we purchase as aquarium janitors (Abbott, 2003). Or they may be introduced with live foods, or even among Artemia cysts, in some cases it seems. They can even be transferred from tank to tank in the aerosol mist arising from an airstone or the bubble stream of a protein skimmer.

It can be very challenging to identify hydroids because there are about a zillion different species of hydrozoans and the different types have different characteristics and are often vary remarkably in appearance. There is considerable variation within the species as well, and the same type of hydroids can appear vastly different depending on the size of the colony and its stage of development, conditions in the aquarium, and their predominant diet. And, of course, the different stages of the life cycle of these amazing animals are so entirely different that they were long believed to be different types of cnidarians altogether, and different species names were often assigned to the same hydroid in different phases of its life cycle. Because they are so difficult to identify and are not easy to distinguished with the naked eye during their initial stages, hydroids often go undetected in nursery and rearing tanks until they begin to take a toll on the fry.

The typical hydroid colony has a stem with a variable number of polyps growing on it, and each of these polyps bears numerous tentacles that are liberally studded with knobby nematocysts (batteries of deadly stinging cells). There are many different kinds of hydroids and they appear in the aquarium in many different guises: many colonies are stalked; some have fingerlike projections, others look like tiny pink fuzzy balls or appear like cobwebs (the webbing kind usually spread along the bottom or grow on the aquarium glass along the substrate). The “snowflake” type of hydroids seem to be particularly common in aquaria, whereas other species look more like crystal chandeliers, and some species form bushy colonies as they grow that serve as microhabitats for Caprellid skeleton shrimp and other tiny crustaceans.

Even a large hydroid colony appears harmless to the naked eye of the untrained observer. It takes a much closer look to reveal the dreaded ‘droid’s lethal nature, as described below:

“Studying the colony under high magnification, one soon becomes lost in an extraordinarily complex, living world–a microcosm in which a beautiful but deadly ballet is conducted on a microscopic scale (Rudloe, 1971). Hungry polyps, some resembling snapdragons, others looking more like daisies or tulips, expand their knobby, translucent tentacles, slowly flexing and languidly waving them about, lulling the observer with their slow-motion ballet — until they abruptly and quite unexpectedly snap up a bit of planktonic life, stinging it, drawing it in with one violent contraction, digesting it, and then re-expanding like a blossoming flower to hunt again (Rudloe, 1971). There are many such polyps in a colony, hundreds of them, each of which is armed with many tentacles and countless nematocysts, and at any given moment, some of them will be dormant and still, some will be expanded and lazily casting about for prey (Rudloe, 1971), and still others actively feeding (Abbott, 2003).”

The feeding or nutritive zooids are the distinct individual animals in a hydroid colony that are responsible for capturing and digesting prey; as such, they bear the nematocyst-studded tentacles. But you need high magnification in order to appreciate the true beauty of living hydrozoans, or to differentiate between different species of hydroids, or to observe the zooids going about their deadly business.

Hydroids are insidious because they start out so small and insignificant, yet spread so quickly under ideal conditions (e.g., a nursery tank or dwarf seahorse tank receiving daily feedings of Artemia nauplii). Many species can spread asexually by fragmentation as a microscopic speck of the parent colony. All of the troublesome types have a mobile hydromedusae stage, which look like miniscule micro-jellyfish, and can spread sexually in this way as well (Rudloe, 1971). The mobile medusae swim about with a herky-jerky, pulsating motion and are often mistaken for tiny bubbles due to their silvery, transparent, hemispherical bodies (Rudloe, 1977). These tiny jellies often go unrecognized until they begin to settle and are discovered adhering to the tank walls. They will have a large “dot” in the middle of their bodies and smaller ones at the base of their nematocysts (Abbott, 2003). Both the polyp stage and the medusa stage sting (Rudloe, 1977) and are capable of killing or injuring seahorse fry. Multiple stings can kill the babies outright, but they are often only injured by the nematocysts, which damage their integument and leave them vulnerable to secondary infections. Many times it is a secondary bacterial or fungal infection that sets in at the site of the injury which kills the affected seahorse.

Once they find their way into a dwarf seahorse setup or nursery tank, hydroids can explode to plague proportions very quickly because conditions are ideal for their growth: perfect temperatures, an abundance of planktonic prey that is renewed every few hours, and a complete absence of predators.

When hydroids become a problem in the nursery or dwarf tank, there is a good way to eradicate them and get the situation under control again:

Eliminating Hydroids

Hydroids can be controlled in the aquarium by using a medication known as fenbendazole to treat the tank over a period of days. Fenbendazole (brand name Panacur) is an inexpensive anthelmintic agent (dewormer) used for large animals such as horses, and the de-worming granules can be obtained without a prescription from stores that carry agricultural products (e.g., farm and ranch equipment, farming supplies and products, veterinary supplies, livestock and horse supplies, livestock and horse feed). If you live in a rural area, those would be good places to obtain it as well.

You can sometimes also obtain the Panacur online from Dr.’s Foster & Smith.

However, there are a couple of things you should keep in mind when treating an aquarium with fenbendazole, Waterdancer. Administering a regimen of fenbendazole (FBZ) or Panacur will eradicate any hydroids, Aiptasia rock anemones, or bristleworms from live rock or live sand, thereby rendering them completely seahorse safe. The recommended dose is 1/8 teaspoon of the horse dewormer granules (22.2% fenbendazole) per 10 gallons of water. Dose aquarium with 1/8 teaspoon/10 gallons every other day until you have administered a total of 3 such treatments (Liisa Coit, pers. com.). Even one dose will do a fine job of eradicating bristeworms, but Aiptasia rock anemones and hydroids are a bit tougher and may require 2-3 doses to eliminate entirely.

Because fenbendazole is essentially a de-worming agent, it will destroy any bristleworms, flat worms, spaghetti worms or the like. The FBZ or Panacur treatments are best administered to the live rock in a bucket or hospital tank before the LR is introduced in the main tank. Otherwise, the massive die-off of the worm population in the aquarium may require large water changes in order to prevent a dangerous ammonia spike! And after the treatment is completed, its a good idea to add a portion of newly purchased live sand to the system in order to help restore its normal diversity of fauna and microfauna again (Liisa Coit, pers. com.) and to dose the tank with SeaChem Stability for a few days to assure that the biological filtration will continue to function at maximum efficiency.

Fenbendazole does not have any adverse effects on biological filtration, but be aware that it is death to many Cnidarians besides hydroids. Mushrooms and related corals are generally not affected, but expect it to have dire effects on other corals (e.g., sinularias), polyps, gorgonians, and anemones. In general, any Cnidarians with polyps that resemble the stalked family of Hydrozoans are likely to be hit hard by fenbendazole, so don’t use this treatment in a reef tank!

Also be aware that fenbendazole seems to soak into the porous live rock and be absorbed indefinitely. I know one hobbyist who transferred a small piece of live rock that had been treated with fenbendazole (Panacur) months earlier into a reef tank, where it killed the resident starfish and Astrea snails. So enough of the medication may be retained within treated live rock to impact sensitive animals months after the fenbendazole was administered. Don’t treat live rock intended for reef systems with fenbendazole (Panacur)!

But this can actually be a good thing in the dwarf seahorse tank. The fenbendazole that soaks into live rock and is then leached back out again in very small quantities can provide the dwarf seahorse tank with protection against another outbreak of hydroids for many months after the tank is treated.

At the lower dosage recommended for nursery tanks and dwarf seahorse tanks with fry (1/16 tsp. per 10 gallons), fenbendazole normally does not harm cleaner shrimp and decorative shrimp. It will kill starfish but copepods, hermit crabs, and shrimp are normally not affected.

When it comes to snails, Nerites, Ceriths, and Nassarius snails are not affected by the medication and can remain in the aquarium during and after treatment with fenbendazole.
 
On the other hand, Trochus or turbo snails, Astrea snails, and especially Margarita snails are sensitive to fenbendazole/Panacur and should be removed from the aquarium until the treatment regimen has been completed and the fenbendazole has been pulled from the aquarium using activated carbon and/or polyfilter pads for chemical filtration. 

Macroalgae such as the feathery or long-bladed varieties of Caulerpa or Hawaiian Ogo (Gracilaria) are not harmed by exposure to fenbendazole at even triple the normal dose. In fact, if you will be using Caulerpa in your nursery tanks to provide hitching posts for the fry and serve as a form of natural filtration, it’s a very wise precaution indeed to treat them with a regimen of fenbendazole beforehand.

So fenbendazole (FBZ) or Panacur is primarily useful for ridding bare-bottomed nursery tanks and dwarf seahorses setups of hyrdroids and Aiptasia anemones, ridding Caulerpa and other macroalge of hydroids or Aiptasia before its goes into the aquarium, and cleansing live rock of bristleworms, hydroids, and Aiptasia rock anemones before it is introduced to the aquarium.

It can also be used to eradicate bristleworms, hydroids, an Aiptasia from an established aquarium if it does not house sensitive animals such as live corals and gorgonians, starfish, Astrea snails, or tubeworms and other desirable worms that may be harmed by FBZ, providing you monitor the ammonia levels closely and are prepared to deal with the ammonia spike that may result from the sudden death of the worm population.

In summation, sir, if the aquarium with a hydroid problem will be housing live corals at some point, it would be best not to treat it with fenbendazole.

Respectfully,
Pete Giwojna, Ocean Rider Tech Support