Thanks, I believe it may be grapewood. We have many Vineyards near the coast.
I hear mixed results for using it in Aquariums, and Plant Guru Tom Barr said he tried it but no longer uses it .
I may soak it for a while and see what happens. A fungus reportedly appears after a while but can be scraped off and eventually goes away.
Most all woods will develop a fungus initially. Grapevine will decay away quickly in comparison to other woods. Also, don't confuse "hard" and "soft", by feel, with what the wood is. Hard and soft in tree terms is based on it being deciduous.
Adding wood to your aquarium has quite obvious aesthetic benefits which can really transform the look of your tank. However there are other significant benefits too. Aquarium wood can give secretive species a place to live and hide. It can
Yeah, if it's grape, it may have had pesticides applied too. Inverts are often more sensitive to those, even if it's been soaking for a while. Better not to take the chance. Maybe it could be used in your yard as a natural piece of art.