Can you tell if a Sponge alive, dead, or dying?

[Levinson]

Can you tell if a Sponge alive, dead, or dying just by looking at it?
Last time I've been to the LFS, I got two chunks of semi transparent white sponge from their sump and put them into my tank. One in the AIO chamber and one in the display tank.
Would I be able to tell if it is dying or dead?

 

[Timfish]

Depends a lot on the species and what live or dead looks like. For most species there's some kind of color change and/or change in surface texture. Best indicator it's alive though is seeing growth over time so patience is needed. most cryptic sponges don't like very much light so be sure the piece you place in your DT is in a dark area.

 

[elysics]

Telling whether it's dying is hard except taking photo time series over months and looking for growth. Also depends on the definition of dying I guess

Telling whether it's (still) alive is easy, take some dye (for example baking yeast dissolved in water, that's in many foods anyway, or the glowing green red sea stuff with actual dye) and squirt a bit at the pores of the sponge. If it comes obviously jetting out of the sponges vents (much bigger holes than the pores) then it is alive

 

[Levinson]

Thank you. I will look into what I can get to test if it's alive.
Judging from where it was growing, it was cryptic so I put one in the dark AIO chamber, another under a rock in DT. I've always wanted sponges of any kind and got them for free while buying some other things. It's actually a lot more than what I had in mind. I merely wanted to seed some bits but got 2 massive chunks instead.
Hopefully they'll settle.