Not a platygyra?

[therealraf02]

Got this sold as a POTO ninja turtle platygyra. The tentacles seem pretty long to me compared to the platygyras i've seen online. Could this be a hydophora?

 

[Saltyreef]

Def looks like hydno to me.

 

[thamnasteroid]

+1 on Hydnophora, specifically exesa

 

[therealraf02]

Hmm, confirms my suspicion then. Anything I should know about these particular guys other than the fact that they are very aggressive? Where would be a good place to place it? It's a 20 gallon high...