Traditionally, it's really hard to raise sharks from eggs. You need to put it in an area of high oxygenated flow, and off the sandbed. So grab one of those seaweed clips, and attach it to the glass next to a pump or something. I think you may also need to drip acclimate it as well.
Even after the shark hatches, you need to get it to feed, and feed SOON! Traditional first foods aren't going to work (i.e. Baby Brine, microworms, rotifers, etc.). Your new baby wants meat, and lots of it. I think that it's recommended you try to feed live shrimp or worms. I'm around 25% positive that Glycera dibranchiata (a polychaete worm used for fishing) is a somewhat suitable first food. But you need to get the baby shark to feed within the first 3 days, or it will die. At this point, the pup will be finishing up absorbing the remains of its yolk sack.
Once you get it onto live foods, then weaned onto frozen, the major parts of keeping the shark are over. However, do know that pups grow fast. They require lots of feeding in this stage, and high water quality. Expect to be able to move it to a 180 gallon aquarium or bigger within a year. Yes, a year.
+1 on the bamboo mermaid's purse. Google "bamboo shark egg" and "cat shark egg", and you'll see the difference.
If you're still wanting the shark, I recommend the following:
Keep the egg in a 29 or 30 gallon tank. Use a very powerful skimmer to keep water clean and oxygenated. You may want an intermediary tank, such as a 75 to grow the bamboo a little more, then it can finally be moved into the 180. Feed high quality foods, like fresh shrimp, squid, and fish like silversides, as well as a special shark formula food. Sharks can develop goiters due to lack of iodine in the diet, so if you see a goiter start to form, better start checking in the fish disease forum here.
