If you have a species only tank or could what do/would you keep in it?

[ISpeakForTheSeas]

For fish, I'd probably go with frogfish.

For inverts, my dream's nautiluses.

Another I would consider are one of the Eusocial Snapping Shrimp species (Synalpheus spp.; Synalpheus regalis is the best known, but there are reportedly a couple other species from the genus which exhibit this behavior as well) - these form ant-like colonies with one reproductive queen and several "workers" in the colony; they also live inside of and defend a home sponge.

And, there's also the Semi-terrestrial Shrimp species (Merguia spp.; M. oligodon and M. rhizophorae) which can climb trees and hop away from danger - these would be cool to setup a paludarium for.

 

[toi_ss]

Cheilinus undulatus

 

[Joeganja]

I don’t have a green thumb unfortunately. I’m better built for saltwater as a hobby rather than freshwater but I’ve seen some incredible freshwater planter tanks and I’ve seen videos of Julian Sprung’s saltwater planted tank and I think I’d dream of doing either or but probably learn towards freshwater to keep myself from adding coral to that tank and keep it solely planted with tetras and rasboras and shrimp.

 

[skey44]

Torch corals!