Fish, Tanks and Ponds


Fish, Tanks and Ponds
A comprehensive guide to fish

Fish treatments

Checkerboard cichlid, Dicrossus filamentosa
Checkerboard cichlid, Dicrossus filamentosa

What can you expect from these remedies?

These remedies along with their commercial counterparts are great for treating some illnesses and will have little or no effect on others. Protozoa infections such as white spot are easily cured but more serious internal injuries, tumours or organ failure obviously won't respond to a few drops of some potion or other. Be realistic with expectations about what can and what can't be treated. If a fish has a very obvious serious illness such as dropsy then euthanasia should be considered as the best way to prevent further suffering.

Acriflavine:

Can be used with fish which are sensitive to malachite green. It is a wide spectrum remedy.

Acriflavine will treat:
Some protozoa diseases like velvet.
Fungal infections.
Wounds.
Some external bacterial infections. Such as flexibacter (mouth fungus - which is actually a bacterial infection).

Dosage:
Using a 1% solution add 10mls/450litres
1% solution applied topically to wounds or fungal infections

Acriflavine is said to interfere with the spread of lymphocystis but this has not been proved.

Copper sulphate

Must be used with great care because copper is very toxic to fish. It is lethal to almost all inverts in both fresh and salt water.

Copper sulphate treats:

  • Snail control.
  • Some external parasites including some protozoa and argulus.

Dosages:

  • Up to 20ppm (20mg/litre). Use a copper test kit to ensure this level is not exceeded. Copper is difficult to remove from the aquarium once it is in there. Biomarine Polyfiters will remove it from the water.
  • Don't use copper when there are inverts present or with Rays and sharks.

Copper sulphate is not the recommended first choice treatment except for snail control due to its toxicity to fish.

Formalin

Is a known carcinogen so avoid contact with skin when using it. Formalin has a variety of uses for treating fish but it is primarily used to treat external parasites. It can be used in combination with malachite green to make a wide spectrum remedy. Formalin will reduce the amount of free oxygen in water so it is important to aerate the water when it is being used.

Formalin treats:

  • External parasites including the surfaces of gills.
  • Protozoa infections.
  • Egg fungus.

Dosages:

  • Formalin can be delivered in a short-term bath at a concentration of 250 mg/l - or 150 mg/l if water temperature is greater than 70F (21C) - for no more than 60 minutes.
  • It can be delivered as an indefinite bath at a concentration of 15 to 25 mg/l.

Hydrogen peroxide

Is another common compound which has a number of uses for fish keepers. It's primary use is to add oxygen to the water very quickly. If a fish is found alive after jumping from its tank, if a fish has been kept in a bag after purchase for to long or if there has been some equipment failure and the aquarium is found to be hypoxic (low in oxygen) then adding:

Hydrogen peroxide treats:

Hypoxia (low environmental oxygen levels).

Dosage:

  • 1ml of a 3% solution of hydrogen peroxide per 4.5 litres of water (mix with a small amount of water before adding to the aquarium).

will very rapidly boost the oxygen level in the water and buy enough time to sort things out properly. Do not under any circumstances add more than the recommended dosage in the mistaken belief that you are giving a little extra help because you may end up making things much worse.

How it works
Hydrogen peroxide (H2O2) rapidly breaks down in water to make 2(H2O)+O2 (water plus oxygen). As you can see there is no harmful residue left over from this treatment so there is no need for water changes.

Malachite green

Is one of the best treatments for fungus on fish. It can also be used to treat some external parasites.
Some fish such as scaleless species are susceptible to it and it may cause more problems than it solves, so don't use malachite green on fish known to be sensitive to medications.

Malachite green is banned for use on humans due to its toxicity, fish which have been treated with it should not enter the food chain and protective gloves should be worn when using it.

Malachite green treats:

  • Fungus.
  • Protozoa infections.

Dosages:

  • 0.1mg/litre for long term baths.
  • 2mg/litre for a 30minute bath.
  • 50mg/litre for a 30second dip.

Magnesium sulphate (Epsom salts)

Magnesium sulphate's main use is to treat digestive problems in fish. Use a separate container to treat the fish rather than add Epsom salt to the tank.

Magnesium sulphate treats:

  • Constipation.

Dosage:

  • 2.5gm/18litres of water.

Epsom salts are also used to harden soft water in order to keep Rift valley cichlids. But this should be avoided due to it's laxative effect on fishes. Fancy goldfish often suffer from trapped air which makes them buoyant. This is often mistaken for a swim bladder problem when in fact it is a digestive problem which in most cases is easily cured with Epsom salts.

Methylene blue

This is one of more traditional older treatments which is generally poorly understood. It isn't just an harmless dye it is actually quite a strong disinfectant.

Methylene blue treats:

  • Some protozoa diseases such as white spot.
  • It is an antidote to cyanide poisoning.
  • Methemoglobinemia caused by exposure to nitrite.
  • Fungus.
  • Prevents secondary infections of injuries.

Treatment should be carried out in a separate tank because methylene blue will interfere with the filter bacteria possibly causing a rise in both ammonia and nitrite in well established aquariums.

Dosage: methylene blue should used at 2mg/litre in a long term bath for around 48 hrs.

Oil of cloves

Oil of cloves has a couple of uses, it is used to sedate large fish so that ulcers, wounds, loose scales ect can be safely dealt with without the fish risking further injury by flapping around. Great care must be taken when using oil of cloves because it is a true anaesthetic and the longer the fish is exposed to it the deeper the fish will be anaesthetised even to the point of cardiac arrest quickly followed by death.

It can also be used to euthanize fish which are terminally ill and suffering needlessly. Because it is a true anaesthetic the fish will become almost immediately numb on contact with oil of cloves and it's level of awareness very quickly falls. This makes it ideal as a sedative and perhaps the most humane method of euthanasia.

Dosages:

  • Sedation - 10 drops per litre
  • Euthanasia - 25 drops per litre

Even if a sedation dose is administered death will still occur if the fish is left exposed to the mixture for long enough. But with the increased euthanasia dose death will occur far more rapidly and without causing any undue distress to the fish.

Potassium permanganate

Isn't widely used anymore due to its toxicity but it is a very good treatment for heavy infestations of external parasites especially on pond fish. It is also used to sterilize equipment such as nets ect.

Potassium permanganate treats:

  • External parasites.
  • Sterilises equipment.
  • Sterilises plants before introduction to an aquarium.

Dosage:

  • Anti parasitic - 2mg/litre as a long term bath.
  • Rift valley cichlids are sensitive to potassium permanganate so the dosage should be halved to 1mg/litre.
  • Sterilisation - 10mg/litre

Caution:
Never use potassium permanganate with formalin. Overdoses will prove lethal to fish. Potassium permanganate will lower the oxygen level of the water, after treatment hydrogen peroxide will quickly restore the oxygen level back to normal, it can also be used when an accidental overdose of pp has been administered.

Povidone-iodine

Has both anti-bacterial and anti-fungal properties. It is mainly used to treat wounds and fungus.

Povidone iodine treats:

  • Wounds
  • Fungus

Dosage: Apply topically with a soft brush.

Salt (sodium chloride)

Salt is a great remedy for all kinds of fish health problems, it is a bactericide, fungicide and it will also kill some protozoa and other parasites. In an emergency use whatever salt you have to hand other than marine salt because marine salt contains buffers which may affect the pH quite drastically by raising it to around pH8.4. It is often repeated that table salt must not be used due to the anti caking additives which it is said may harm fish. I believe that this is simply being repeated quite blindly by people who have no experience of it. I and many others have used it in an emergency without any ill effect what so ever, indeed I have never heard of any fish coming to harm which could be attributed to using table salt instead of some other type of salt.

*If salt is safe to use then table salt is safe to use.

  • 0.01% solution (1gm/10litres) used for making nitrite less toxic to fish.
  • 0.1% solution (1gm/litre) added to aquarium for fish such as mollies provided that tank mates need similar conditions. (use marine salt only)
  • 0.1 to 0.3% solution (1 to 3gms/litre) used as a long term bath for treating traumas (physical damage) and fungal infections until healing begins.
  • 0.3 to 0.5% solution (3 to 5gms/litre) used to eradicate hydra.
  • 1% solution (10gms/litre) used as a long term bath to treat fish with ulcers.
  • 2 to 3% solution (20 to 30gms/litre) used as a short term bath for less than an hour to treat fish with leeches.

Tips on using salt

Where possible always use a separate container to treat the fish rather than add salt to an aquarium because some fish are quite intolerant of salt and its addition to their water will place the fish under stress.

Where solutions above 0.3% are to be used it is a good idea to begin with a weaker solution and increase the salt level daily over a few days rather than risk shocking the fish.

Don't use salt in planted tanks, few plants will thrive with salt in the water.

Before using salt as a remedy make sure the fish being treated is salt tolerant.

Don't add salt to fresh water aquariums thinking it will act as a preventative measure against illness, fresh water fish live best in fresh water - i.e. no added salt.

See Treatment finder for commercial treatment

About this page

Commercial treatments use the same few compounds in differing proportions for many of the remedies sold in fish stores. These compounds are available to buy on their own usually from koi dealers because pond keepers tend to use this type of remedy in preference to store bought remedies which often don't list their ingredients. None of the treatments mentioned here are classed as controlled medications and are freely available to buy over the counter at the time of writing (2012).