Anyone know exactly what this is ?

[Rjmul]

It looks like a spider sponge, but it's not. Seller doesn't know either

 

[tsouth]

These are gorgonians. Non photosynthetic species and filter feeders. I'll have names for you in a moment.

Edit: Crabs backed me up. Ty sir

 

[Crabs McJones]

Gargonian coral

https://www.liveaquaria.com/product/1519/?pcatid=1519

 

[Rjmul]

These are gorgonians. Non photosynthetic species and filter feeders. I'll have names for you in a moment.

Edit: Crabs backed me up. Ty sir

Nice. So I don't have to treat this like a sponge I don't have to dump the stores water in my tank. It can be exposed to air?

 

[AcroNem]

Diodogordia nodulifera, both colors same species. They need consistent feeding. As in as often as you can feed them, and laminar flow, or they will starve.

 

[tsouth]

Nice. So I don't have to treat this like a sponge I don't have to dump the stores water in my tank. It can be exposed to air?

Some species will best be treated without being exposed to air. No, do not dump the store water in your tank. You can continually acclimate until you've effectively removed as much store water as possible and replaced it with your own tank water. Then place the container into your tank and move the coral from there.

More importantly, the requirements of some gorgonians, like the ones pictured, are incredibly needy. As mentioned above by Acronem, feeding and flow. There are some tricks i've read in the past such as placing a 2-liter above the gorgonian and squirting food into it.

Best of luck to you