Oh sorry Frank, I meant clip the end of the shark egg to one of the clips some Hobbyists use for holding veggies for their herbivores. The clips have a suction cup.
Nice to see your retifers are doing so well. You female is obviously mature, is your male there yet? You'll know if the egg isn't viable because the yolk will drop. The yolk will also lose its round/oval shape and more flat along the top. When you rotate it, the texture of the yolk will seem "chalky." If it's viable, the yolk will keep its shape and a vein will appear. Eventually you'll see something twitching off the yolk.
Any chance you might start selling pups if you get viable offspring? I'm interested in having one or two of these guys but I can't find them for sale anywhere!