Have you any idea what species you're looking to get ? Some are only 2" or 3" while others can grow up to about 9" so it's sorta important before I can say what size tank. While these are sedentary fish they are messy so good filtration or skimming is a must. Lighting is really of no importance so high light is not needed. Most of these fish when first aquired require live foods normally small fish ( not freshwater ) but can be weaned to meaty foods such as pieces of shrimp, squid, silversides, etc. Lastly do not keep with small tankmates i.e. fish, snails, crabs, shrimp as they will be consumed.
HTH
Regards,
David Mohr