I have a 20g reef tank that i set up when i signed up for ARC. currently i have a mckoskers wrasse, a canary blenny, and a two spot goby. with the two spot i have a pistol. i also have a cleaner shrimp, a peppermint, a fighting conch, sally lightfoot, emerald crab, porcelain crab, horseshoe crab and various hermits and snails. anyone have suggestions on what to get next for the tank?