I got four peacock gobies (Tateurndina ocellicauda) two and a half weeks ago. They certainly like the slate caves - a pair spawned in one yesterday evening! They like small spaces to spawn so Adam made me some 1 x 1 x 3 inches, and they did the trick. And they look much nicer than the bits of plastic tube I was going to use.
i got two of these caves. found adam very helpful and they arrived quickly. tied some java moss to them and it looks really nice in my tank , kuhli loaches are loving it and my pleco quite likes his too