Looking for a sea cucumber for my tank

[Zante]

I have a Fiji biotope aquarium, and I've been very careful of sourcing nly species that can be found in Fiji. Even the rocks come from Fiji.

I am now looking for a sea cucumber, but I'm finding difficulty in finding information on them and the particular species.

I have a way of checking the distribution of a species once I have the scientific name, but I'm not finding much info on the species themselves.

Where can I find a list of species that will live in a 150 gallon aquarium?
I don't want to end up with a species that will grow to 3 feet in length or more.

I have spied a species I might be interested in: Thelenota ananas
Anyone have experience with it?

 

[Zante]

Addendum:
I am also planning a sand anemone for my clowns, either a carpet anemone or a sebae anemone. Since the sea cucumber and the anemone are going to share the sand bed would that be a problem?

I know I don't need ananemone for my clowns, they have been fine for a year without. I like anemones and I want one.

 

[Zante]

Anyone?