Rodeo, Eagre, Aquamaster, Glypro, Aquapro, Aquaneat, and several others, are all 53.8% glyphosate without a surfactant. Monsanto, whose patent expired on glyphosate, sold the brand-name "Rodeo" to Dow a couple of years ago and then immediately introduced "Aquamaster". Griffin (who formerly marketed Eagre) has now abandoned this market due to the declining prices - as will several of the others suppliers before the dust settles. So, your sources for Eagre will likely dry-up this season - but several very economical brands will remain. The concerns associated with using Roundup in ponds isn't fish mortality. Rather, the tallow-amine surfactant found in Roundup has shown to cause problems with aquatic invertebrates, clouding fish cornea and causing gill irritation (at what concentrations I do not know). Use one of the aquatic-labeled glyphosate formulations and sleep well. With the rapidly falling price tags, there is absolutely no reason to take any risks. The earlier comment suggesting to wait until the catkin (seed head) has begun to form is very good advice.
