Twisted,
Interesting design. I have made a few PVC pipe caves coated both inside and outside with a thin layer of epoxy then rolled in play or pool filter sand. Loose sand then falls off after the epoxy has cured and those look nice. Hope they work well so you can take photos from a rather unique perspective.
Some Loricariidae do not mind smooth interiors and some prefer a textured interior but this depends not only on the species involved but also on individual fishes preferences.
I usually use epoxy on plastics as I get a stronger bond than that of silicone sealant but the fit between pieces needs to be very good. I do use silicone sealant on the rectangular ceramic tile caves. Silicone sealant allows for filling in any unevenly cut pieces which can make up for the relative lack of bond strength.
"Barbara Odgers" <Barbara Odgers <
[email protected]>>, made my last batch of 16 caves out of fired clay.
She will make them to your specifications and Discus spawning cones, too.
It was still too cold for me to want to cut ceramic floor tiles over at my buddy's work shop. He owns a rock, gem and jewelry shop but his water lubricated rock saws spray ice cold water on me which I did not feel like dealing with in February.
Avid Trout fly fisherman. ·´¯`·...¸><)))º>