Peracetic acid as an alternative to malachite green as a fungicide.

Following the recent post on the potential for saprolegniasis affecting fish after a cold snap (mainly from depressed host immunity), many fish owners turn to malachite green as a potent antifungal cure. This chemical is still widely available in the ornamental fish sector.

But did you know that malachite green has long been banned for use in food fish production because of their carcinogenic potential. Actually, I met a guy who had inadvertently treated his silver perch with this chemical, only to find out some time later that it’s rather toxic and banned for use in food fish. So, he can’t eat his fish and instead, his cultured fish will now become lifelong pets.

This paper describes a different compound (peracetic acid) that may warrant further investigation and it could be something that can be used safely for fish that are destined for human consumption.

Journal of Fish Diseases
Volume 35, Number 7 (July 2012)
	Peracetic acid is effective for controlling fungus on channel catfish eggs
	Authors:	D L Straus 1, T Meinelt 2, B D Farmer 1, A J Mitchell 1
	Author Affiliations:	1: U.S. Department of Agriculture, Agricultural Research Service, Harry K. Dupree – Stuttgart National Aquaculture Research Center, Stuttgart, AR, USA 2: Department of Aquaculture and Ecophysiology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany
	Source:	Journal of Fish Diseases, Volume 35, Number 7 (July 2012)
	Page Numbers:	505 – 511
	Available Full Text:	Full Text: Subscription Required to view full text Format: PDF Size: unknown Location: Publisher’s Site Authentication: EBSCOhost EJS
	Abstract:	Peracetic acid (PAA) is a relatively new compound suggested for use to treat pathogens in aquaculture. It is approved for use in Europe, but not in the United States. This study determined the effectiveness of PAA for fungus control on channel catfish, Ictalurus punctatus(Rafinesque), eggs. The study consisted of five PAA concentrations (2.5, 5, 10, 15 and 20 mg L-1) and an untreated control in a flow-through system. A single spawn was used for each replication (N= 4). Eggs were treated twice daily until the embryos developed eyes. When hatching was complete for all viable eggs, fry were counted to determine the percent survival in each treatment. Fungal growth was severe in the untreated controls resulting in 11% survival. Treatments of 2.5, 5 and 10 mg L-1PAA were significantly different from the controls (P <;0.05). The highest percent survival of hatched fry was with 5 mg L-1PAA administered twice daily; the 2.5 mg L-1PAA treatment had slightly less survival, but gives a higher margin of safety in case of treatment error. Very little fungus was present in treatments receiving 2.5 mg L-1PAA or higher, and concentrations of 15 and 20 mg L-1PAA were toxic to the eggs. The mean survivals in the 0, 2.5, 5, 10, 15 and 20 mg L-1PAA treatments were 11%, 60%, 63%, 62%, 32% and 0%, respectively. Therefore, PAA may be a compound that merits further investigations regarding its use in U.S. aquaculture.
	Citation:	D L Straus, T Meinelt, B D Farmer, A J Mitchell . Peracetic acid is effective for controlling fungus on channel catfish eggs. Journal of Fish Diseases, Volume 35, Number 7 (July 2012), pp. 505-511, ;
	URL:	http://ejournals.ebsco.com/direct.asp?ArticleID=44C3AF30379B5B3A5154

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