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I'm new to keeping Corydoras (Aeneas, Metae and probable Agazizii) and I've just bought some alder cones. I've read a lot about using BLACK alder, but does anybody know if you can use the cones of the Red ALDER (Alnus rubra) that grows around Portland, Oregon? I just found a tree right next to where I live and can't see any difference between the catkins of it and some I bought from a guy in Poland, but I'm no botanist.
Also, I've read about using oak and Ketapang leaves for the same effect. Has anybody used alder leaves?

I'm in Washington state in the desert about 150 miles from you, we drive to Portland to the Wet spot and the shops in your area quite often, I've stopped along the way to pick Oak leaves and have dried and used them, and I buy the Ketapang leaves from Amy off of eBay. I use the leaves in my fry tanks and I personally believe that my fry grow faster with some leaves in the tank, I see them eating whatever the small stuff is that grows on the leaves as the leaves break down. I bought some Black Alder cones from a UK seller on eBay and tried them in a tub with eggs as I heard that they are better than using Methlyene Blue. I wasn't impressed, but that's not to say that they are not useful. I don't know if the Red species are the same or not.
BTW: if you got your Corydoras agassizii from the Wet spot, then they are actually Corydoras leucomelas.
Kind Regards,
Don

Thanks, Don. Actually, I bought the (possibly) agazizii from the Wet Spot as punctatus but when I looked them up online they were not. The species you suggested differ from the five I have by the black on the dorsal fin -- mine have their black on the fore edge, but I'll look again and compare to other species.

Don, on closer inspection, you are probably right. leucomelas it is. Thanks.

Hi all,
Alnus rubra is fine to use. I haven't tried Alder leaves, but Alder bark has been used for tanning leather in the past (like Oak), and the wood is rot resistant, so I would expect that they are similar to Oak leaves in the secondary metabolite compounds they contain.

I'm not sure any-one has worked on them as anti-microbials for aquariums, but there has been some ethno-botanic work <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3263052/>.

cheers Darrel

Hi all,
Couple more Alnus references,

The methanol extract of the bark of Alnus rubra showed antimicrobial activity against Gram-positive and Gram-negative bacteria. Diarylheptanoid and its glycoside (oregonin) were identified as the two constituents responsible for this activity."

from: SAXENA G. et al, (1995) "Antimicrobial compounds from Alnus rubra" International Journal of Pharmaceutical Botany 33 pp33-36.

I've not had a proper look through it yet, but Citarasu, T. (2010) "Herbal biomedicines: a new opportunity for aquaculture industry" Aquaculture International 18:3, 403-414 looks very interesting <http://www.springerlink.com/content/tv4 ... lltext.pdf>.

cheers Darrel

HI OC,
Yes, I spoke with Tavis at WS about them as they have had them as puntutas as well as agassazi..
I also think Ian Fuller identified them in another post as leucomelas. (pertaining to them from a hobbyist from Portland)
Regardless, The crew at Wet Spot are really great and have fantastic fish, I enjoy each and every visit! Consider the ample Oak leaves that are in your area, be sure to dry them out, but, they are very useful and will lower the pH as well.
Don