Hi, you left us very little information to work with here.
I have an 800 gallon tank with 4 sharks, so I hope I can help a little, but not sure, as I don't have enough info.
180 is okay for a shark and very little else as long as the shark is small. A coral cat may be better for you.
Your tank must be completely cycled. You should have a couple inches of nice fine coral sand. Some live rock is very good, but must have sand for the sharks to lay in and "walk" around in. You must have excellent filtration - there is never too much filtration. Your nitrates should be at zero if not close. Your ammonia has to be zero or close - not medium, zero or close. Your ph should be 7.9 to 8.3. I have extremely high nitrates that I'm trying to work on, so there is always something to watch with a shark tank. You must always test your water before you change your water. You don't want your fish to go thru any shock. Your temp should be in the 70's - 72 is fine.
Now, lions are very tough on your system. I have not have much luck with them, yet many people love them. They also could sting your shark, you never know.
Do not add any shark until all perameters are perfect. Small sharks are very delicate and you do not want to hurt another shark.
After a couple months of acclimation - be patient -and make sure your tanks has fully cycled, you may add a shark. An eel would be a good companion also - snowflake is perfect. As for more active fish, be very careful as some fish pick at shark eyes thinking they are crustaceans and then you have a blind shark. No matter what anyone says, sharks are delicate creatures and must be treated with extreme care.
Never get triggers, puffers, angels. Never get fish that get too big - I don't suggest any groupers of course or lions. Two tangs, a coral cat, and a snowflake eel would be enough to too much, after acclimation. Make sure you over circulate your tank - a lot of water flow is never too much and a lot of filtration. Do not overfeed. Feed every other day, but tangs can eat some seaweed everyday. You should turn off your filter and water flow while feeding the shark and eel so that it does not sit there and not get eaten. Be slow with feeding. 180 gallons is actually a small tank by shark standards. Be patient, get a book on sharks and eels, or I really suggest the Conscientious Marine Aquarist by Fenner. I refer to it a lot. Good luck and be patient!
i just bought a 8 inch banded cat shark from my lfs yesterday
