My Friend’s 5.5 Gallon Saltwater Tank
Yes, the smaller the tank, the harder it is to care for and keep alive. We bought our friend a 5.5 gallon saltwater tank this spring and it is alive and doing well.
The main inhabitant is an emerald crab that liked to knock over coral in our tank, Tanner took him home and put him in his nano tank. He likes to hang out during the daytime a lot more in the little tank (he typically hid a lot in our tank and came out at nighttime, we have a lot of saltwater fish though).
Tanner also has a xenya tree that was a resident in our tank (it was much smaller when it came out of our tank, it has grown a lot now!)