Maintaining a quarentine tank?

A one gallon is too small for almost all aquarium fishes, with even a betta being a maybe.

Atleast a 5g, not becuase of stocking but becuase these fish need space to move. You could probably get away with 6 at the most small tetras or guppys (maybe about 3/8 inch max), but I would go with a 10g for a quarantine, this way you won't have to upgrade it when you get another tank and the price of a basic 5g or 10g setup works out to be about the same around here, not sure about your area though.

Keeping some snails and shrimp, with filter running and regular pwc will give you a continuing ready-to-use quarantine tank. Maybe a couple of hardy live plants, too--live things which will keep the ammonia and other stuff going (poo, decayed plant matter). Just treat it like your other tank WITH healthy fishes. One thing to consider is you often don't want your itty bitty fish moving too terribly much, just enough to get exercise and oxygen movement thru gills; for the little livebearers or guppies I think a 2.5 to 5g should be sufficient. If you move up to larger fishes, then you will want a larger quarantine tank; they'll need to be in there for anywhere from a week to several, depending. Hope that helps!! (It's how I maintain a successful quarantine/hospital tank, but a 10g for larger fish.)

10g tanks tend to be the absolute cheapest. smaller than a 10g they get more expensive, and larger than a 10g (obviously) they get more $$$ a 5g here is about $15, a 10g is $10 and the filter and heater and all that are about the same.

Most of the liquid/tablet meds I've got have instructions that use dosage/10gallons as an almost standard unit of dosing measurement.

Using a smaller tank, you might underdose or overdose. Just easier to use meds packaged in "10-gallon increments" in a 10-gallon hospital or quarantine tank.

v/r, N-A

I concur on the 10 gal size. 2-3 days is not sufficient for Q. For tank raised fish allow at least 2 weeks, for wild caughts a minimum of a month. And what this means is they must be in the tank for that length of time without any fish deaths or signs of illness. If one dies or you treat the tank, then the time period restarts effective with the death or the end of the treatment.