I have a bunch of Scyphozoa and other jellyfish that are have been in 5-10% formalin for at least a decade. Is it safe to transfer those to 70% ethanol? Any downsides?
I do know that jellies need to be strongly fixed in formalin (or some other aldehyde), but once they are fixed, can they be transferred to the less toxic ethanol?
Dan, I've transferred some Scyphozoa (Stomolophus meleagris, Cyanea capillata, Aurelia aurita) and some Anthozoa (Physalia physalis, Porpita porpita) to 70% ethanol decades ago and they seem to have retained form (of course, not color) to date. You'll need to wash the formalin with tap water many times and then to insure removal of as much formalin as possible I'd use running tap water overnight (if you do the initial changes of formalin and water many times there shouldn't be much formalin left in the specimen by the time you use running tap water). Of course those earlier changes need to be done under a hood and waste formalin safely stored for appropriate disposal. The initial addition of ethanol could cloud if some formalin is left but you'll want to do several changes here before final storage. I'm not sure whether the decade of storage in formalin will make a difference or not; specimens I moved were in formalin not for many years but some were in for formalin for months to a year or two. Bob
Thanks Robert. Well understood re washing and leaching of traces. Bouins with picric acid keeps coloring ethanol yellow for many changes. Well understood re color. Glad to hear that I can get rid of more formalin in the collection safely.
It depends on the analysis that you will use in the future.
You can let them in water for 2 days and change the water many times to takeaway the big amount of formalin then transfer them to alcohol.I already tried this on gonads of fishes. I don't know for jellies because they are not strong but you can try on one specimen and see.
Good luck 🤞
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