Unidentified sponge

[coldwatertech90]

So this is in a friend’s aiptasia growing tank for feeding his berghia nudis. It’s a type of finger sponge I believe. Its black in color besides the area around the opening at the top of each branch, which is white. Another interesting note is that it will cause a stinging sensation when handled. Has anyone seen this ?

 

[WheatToast]

Cool! I think these have hitchhiked into the tropical reef tank at the Aquarium of the Bay in San Francisco; they almost remind me of the green macroalgae Codium. Could you take pictures under whit light (ex. with a flashlight)?

At the Aquarium of the Bay:

 

[ISpeakForTheSeas]

I agree that pics under white light could be helpful for ID. The stinging sensation is interesting - does the sponge only sting while one is handling it, or does the sensation begin/linger after one is done handling it? If it is the latter, has the stinging sensation been experienced by multiple people, or just one person?