Dear Kris:

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