Well if you don't mind having to treat sick fishes in your main planted display tank, or subject other healthy fishes you may already have to possible treatment's, then quarantine isn't needed.
I keep a small 20 gal tank and sponge filter along with spare heater in a closet.
Week's ahead of purchasing healthy looking fishes (don't buy fish from tanks holding sick/dead fishes), I begin to run the sponge filter in one of my already established tanks so that it can become seeded with bacteria that already exists in the established tanks.
I then fill the tank with dechlorinated water and place the sponge filter and heater in operation on the quarantine tank the day before purchasing the fish, to allow water to come to temperature,and ensure filter is working properly.
I use plastic fern (bamboo) for the fishes to feel a bit more secure.Live plant's would take a hit with use of many medications.
Quarantine for me is about 3 week's when I can stand it.Sometimes sooner (says sheepishly).
Would always use water conditioner such as PRIME or Amquel Plus with water changes during quarantine and or extended acclimation both of these clearly say on the bottle that they detoxify ammonia.(ammonia can build up in bucket/bag during long acclimation
(3 hour's too long)
I feed fish sparingly in quarantine maybe a pinch every couple day's once a day.
Fishes might not begin to feed for a few day's, and any uneaten food's will only work to foul the water.
I don't move sick fishes from display tank to quarantine so same water I use for weekly water changes from my tap in display tanks, is what I use in quarantine.
I have bought fish and placed them directly in my display tank without issues,but..this has backfired on me as well.
Hope some of this helps.
Thank you for reply. But a 20G isn't a "small" tank.
I have shrimps and snail in the planted tank, so using medications isn't an option. I may lose everything including the fish, which in my past experience, the fish are already on the death sentence either way.
Will shorten my acclimation period to an hour. Thanks for the advise.
By the way, if you use dechlorinated water in the QT, would that parameter defers from the display tank? Wouldn't that affect transition?
I think the reason for QT is important here. Reason 1, I think, would be to keep new fish separate from the display tank for however long it takes to determine that they are not sick. I just finished a 4 week QT on some cories, and I wanted them to be happy and relaxed while waiting. So I gave them a thin layer of sand and a couple fake plants for their comfort.
Reason 2 is for a hospital stay to be treated with meds for an illness. Whether or not the fish survives, having a safe comfortable place to be treated is, I believe, reason enough to QT. If nothing else, that sick fish will not be subjected to being picked on, bitten, or eaten alive by his tankmates.
After all, it's about the fish, not our own convenience, right?
I haven't been able to keep fish alive in QT for more than 2 weeks, so it seems challenging to be able to do so for 4 weeks straight.
If I detect an issue with the fish, the time it takes to setup the QT, the fish would have been already close to death. There were a lot of instances where I noted spots on the fish, took out my spare filter and wash, drop in biohome from my established filter, wash the spare pail, added in water from the display, move the fish to QT, dose medication and the next morning-> fish is dead. So to me seems my efforts were uncalled for and a waste of time. Throwing the fish out of the window would have been a better option.