Dear ageber:
The color of the substrate is purely aesthetic. Just go with whatever color of live sand appeals to you. I am one that prefers the black sand in a dwarf seahorse setup, since the pint-size pigmy ponies themselves are often pale in coloration. So the color is purely optional, but the size and depth of the sand bed is very important.
For best results, I find that fine-grained oolitic live sand works well and can help control nitrates. If the substrate is composed of very fine sugar sand, then the detritus and organic matter tend to remain at the surface atop the sand, where your cleanup crew can take care of them.
The depth of a shallow sand bed like this is a crucial factor. Too deep, and you risk anaerobic dead spots where deadly hydrogen sulfide gas can form. Too shallow, and there will be less surface area to support beneficial nitrifying bacteria and Nassarius snails and other beneficial burrowers may feel vulnerable and exposed. A bed of live sand between 1/2 to no more than 1-inch deep is just right for the main tank. A properly layered Deep Live Sand Bed (DLSB) 3-6 inches deep with a full complement of sand shifters also works well with seahorses, but is best confined to a sump rather than the display tank due to the seahorse’s heavy waste production. In other words, you can minimize the buildup of detritus in the DLSB by installing it in your sump rather than the main tank.
Both artificial and natural hitching posts and decorations can be very effective for a seahorse tank. I have seen some very beautiful seahorse setups composed entirely of artificial corals and synthetic plants. They are getting very good at making these faux decorations nowadays, so much so that it can be difficult to tell the fake stuff from the genuine article.
Of course, a well-established, well maintained reef tank brimming with hand picked live corals is a beautiful sight, and seahorses will often do very well in a modified reef system. If you mix in a few pieces of high quality synthetic coral with natural colors among the living corals, it can be hard to tell the difference and may work out very well. But poor quality artificial corals and plants or faux decorations with garish colors may look out of place in a reef setting.
Best of luck with your new seahorse tank, ageber! A 90-gallon aquarium can make an excellent tank for a sizable herd of seahorses.
Respectfully,
Pete Giwojna
Ocean Rider, Inc. is an Organic Hawaiian-Based Seahorse Aqua-Farm & Aquarium that Follows Strict Good Farming Practices in Raising Seahorses and Other Aquatic Life.
