Review: Poly Lab Medic marine fish treatment


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I'm flying blind here as the ingredients listed are vague, but Medic is a treatment for marine fish in reef systems where traditional copper-based medications are out of the equation, writes Nathan Hill.

The treatment claims to act on freshwater and marine whitespot as well as marine velvet disease. On top of that, it claims not to harm nitrifying bacteria, nor invertebrates — unless that invert happens to be a protozoan, I assume.

The (only) ingredients listed are 'crystallised peroxide salts' which I am gambling means the treatment is hydrogen peroxide-based, though I could very easily be wrong.

If it is hydrogen peroxide, then I’m twitchy about the packaging, which comes with neither an oxidising warning, nor potentially explosive, corrosive or irritant warnings — pending exactly which peroxides are included in the treatment.

I was disappointed that when I asked Polyp Lab for COSHH sheet access (or equivalent) I was refused outright.

If you’re going to use this treatment keep it as far from children or other pets as you possibly can. Peroxide can be combustible, burns flesh, will potentially blind and if swallowed can easily hospitalise you. Until I get more information on safety, this will not be going anywhere near my medical kit.

As for efficiency, hydrogen peroxide — assuming this is what Medic is based on — has a good track record. It’s a form of bleach and one that higher organisms and some bacteria can create metabolic enzymes to cope with.

Peroxides have been used to devastating effect on algae in reef tanks and usually without any harmful effects on corals. If it’s not hydrogen peroxide-based, then forget everything I’ve just said.

Medic is added to the tank via a small scoop and is dosed both before turning lights on and after turning them off — which again reinforces my suspicion of it being hydrogen peroxide.

At a dose of one tiny measure per 50 gal of water this is pretty concentrate stuff and can be used for up to 20 consecutive days.

Instructions state that a course of at least ten days needs to be completed. This makes sense considering the lifecycle of protozoans if trying to catch them at their vulnerable, free-swimming theront stage.

During use, UVs and carbon need to be switched off, though skimmers can run as normal. Post treatment, carbon is recommended to pull out any residual, remaining treatment.


Medic has mileage and one only has to look at historic use of peroxides in marine tanks and even aquaculture to note a brilliant success rate. The only stumbling blocks for me are pricing and labeling — the latter of which I find way below par.

Price: £29.99 treats 2,500 l/5,500 gal. More info from Reef Eden International.

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