Malachite green and glutaraldehyde bath(last resort ick treatment)


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Hello everyone, I just wanted to share the results of a recent experiment I did as a last resort to try and save a fish from an extreme ich infestation after introducing a new fish.

The fish in question was a black skirt tetra that was encrusted in a nearly solid layer of ick, she had been floating sideways for the past 6 hours and ick was unresponsive to normal treatment levels of malachite green.

I'm currently in canada and there was recently a ban on nearly every medication used for parasite control in aquariums aside from malachite green.

I initially was thinking of getting some copper sulfate Crystal's to make some homemade "cupramine" but then remembered that paraguard active ingredients were none other than malachite green and glutaraldehyde both of which I happened to have on hand.

I decided to fill a gallon bucket with warm dechlorinated water, 5ml of malachite green solution equaling out to .45mg/ml and 1.6ml of glutaraldehyde in the form of seachem excel.

I proceeded to soak the tetra discussed above as well as another one that was particularly infested for 30 minutes and then transferring back to the aquarium. 3 hours later all physical traces of attached ick have dissapeared from both fish and is still clearly visible on the 5 tetras that went untreated.

The fish I mentioned first is still swimming sideways and doesn't look likely to make it but the second one seems completely renewed.

Just thought I would share incase anyone else was in a situation with nothing available but malachite green.

I've been continuing to dose malachite green in the main tank to hopefully kill the parasites in the water column and gravel.


Fishlore Legend
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Holland (The Netherlands)
More than 10 years
Though I can understand the use of Melachite green I don't understand the one of Gluth which is poisoness to creatures in higher levels. Why the combination.

Also Melachite greem kills the free swimming parasites and not the ones on the fish.

Hoping the others survive.

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