Quarantine Tank?

[Gurglar]

I am going to start up a quarantine tank before getting fish to add to my 35 gallon and have a few question:

How big should a Quarantine tank be?

Will a 3 gallon be alright or can I get a smaller one?

There will only be small fish being kept in it as I do not buy fish that grow any bigger than 2-3 inches.

Can I keep the quarantine tank empty without any substrate or plants and just have a filter and heater in it?

How long should a fish be kept in the quarantine tank when bought from a pet store?

 

[alexdallimore]

This is my own Q tank

22Litres -- Chose this just becuase I was in the LFS and it suited my needs. It also gave fish enough space. Personally I would buy this size again as when the fish get better they are not cramped and can stay in there for a bit longer

When fish have been put into the tank I have no substrate as this means you can see exactly what waste is on the bottom and can get it out easily. I do have one plastic plant in there though to give a bit of shelter so the fish can hide and not be stressed as well as ill.

Not sure on the last question as didn't have the tank when I added fish so have only used as a hospital tank