My ammonia and nitrite levels are at zero now, and nitrates are at a smidge above zero, so it looks like the tank is actually cycling. Yay! I ended up breaking the shark out of his shell. He looks a little worse-for wear I don't know exactly what happened in there but he doesn't seem as graceful as he was before.. but at least he's alive...
Thanks for all the help in getting things where they should be.