Posted on by Richard Lin

All About Clout (Mardel)


Fritz Mardel Clout

I have seen a lot of posts recently about Clout by Mardel.  I have carried Clout in store and also online for well over 2 years so I figured I would do a quick breakdown of Clout, what its made of, what its for and how to use it safely.

Mardel Clout is a VERY powerful, potentially dangerous drug comprised of 2 main active ingredients.  The active ingredients per tab of Clout, as listed on the Mardel website are;

190mg Metronidazole (5 grams/tonne or 5ppm)

7.8mg Trichlorfon (about .2 grams/tonne of water or .2ppm)

Im not going to discuss Metro too far in depth here as its a relatively common drug and can be used in bath and ingestion applications.  These are readily available in the marketplace and can be purchased here. HexShield and Metro+.  

Trichlorfon however is a drug not discussed too often in the goldfish community.  I can tell you its the drug of choice when combating illness in many farms across several countries.  In Japan, many koi farmers routinely use Trichlorfon for treating koi illness. In China and Taiwan, Trichlorfon is also the treatment of choice for many farmers.  

What is Trichlorfon?  Trichlorfon, also known as Dylox is an organophosphate and a neurotoxin.  It has many common applications as a commercial insecticide. When used correctly, it is effective against flukes, lice, leeches, worms and many external parasites including ich.  It is also toxic to snails, invertebrates and crustaceans. When used incorrectly, it can quickly become toxic and lead to death or severe to permanent damage to your fish. Signs of overdose are bent spine and wiplike swimming from which the fish may never recover and of course death.  Trichlorfon also degrades quickly and become unstable in higher temperatures and higher pH. One last scary thing....its also a known carcinogen.

Here is a Trichlorfon treatment gone horribly wrong: Link Where over 100 fish die at public aquarium due to overdose.

Ok, so now that I have scared you, here's how you use Clout without killing your entire tank.  Clout, as shown above has a Trichlorfon concentration of about .2 ppm if dosed according to the bottle.  Advanced hobbyist recommend dosing between .5-1 ppm so as you can see, Clouts dosage is much lower (safer) so there shouldn't be much of a chance of overdose.  Typically, 1 dose is enough to rid the tank/pond of the infestation but a recommended follow up treatment a few days to 1 week later should break the life cycle.  

Here are some of my notes from using this product.  Clout is a good medication to keep in the toolbox. In most cases, praziquantel and formalin will take care of the issues you are dealing with but there will be times, you will come across a parasite or fluke infestation that is either prazi resistant or just cant be treated with prazi.  In these cases, Trichlorfon is a good option. I would not recommend using Trichlorfon as a first step or a cure-all as it is a neurotoxin afterall. Many years ago, Trichlorfon was used excessively and there were some resistant flukes and bugs so many hobbyist found prazi to be more effective.  But the more you talk to oldtimers in the hobby, the more you realize that it all goes in cycles. What I like about Clout is that it is easy to measure and use because it comes in tablet form. The tablets make it very difficult to overdose. Also the low dose of Trichlorfon per tablet make it extra hard to OD.  Whenever you are dealing with commercial products the manufacture will cover themselves and the meds will almost always be watered down. The majority of the tablet is actually Metro. After you dose the tablet, there you will have a lot of white powder metro at the bottom of the tank. Your goldfish will probably eat it and poop white the next day.  Dont be alarmed. Metro ingested is basically the same as Hex Shield by New Life Spectrum. Its good for treating internal parasites if the regiment is kept up for a few days (3). Clout will give your water a slight blue tint for a few hours. Clout does degrade quicker with light so I would recommend turning off your lights when you dose. If you have a UV, make sure that is off as well or the medication is basically useless.  Carbon will inactivate trichlorfon, so make sure you remove that as well. You can use salt with Clout. One last thing. Trichlorfon does go bad. The expired form of trichlorfon is toxic.