I have a 50 mug to keep sea water fish need what equipment.
Light fish, not coral, you can still play, your 50 cylinder is dedicated to sea water
If it is a freshwater tank, then pay attention to the high density of sea water than fresh water
Sea water aquarium special salt, without coral, light can buy cheap
Optical salinity meter, protein separator, and some small equipment, the sea water cylinder must use live stone on these
