That is some great advice 1077. Thank you for your input!
One thing I'd like to add to 1077's info is the storage of nets, especially if they are used for more than 1 tank. Between uses they can be kept in a bucket of salt water to sterilize them. They should be rinsed before putting them into the tanks, but this is a great way to be sure you are not transferring illness/disease from one tank to another. A quick dip, swish, rinse between tanks will help prevent cross contamination between tanks.
I have to disagree with a few things that Byron has stated about QT, please let me explain.
For starters, not everyone has the ability to set up a QT tank as another full time tank just sitting around waiting (and needing to be maintained) between illnesses and new fish purchases. There are some easy ways to set up a safe QT as a temporary situation.
Also please remember that every tank is an individual. Even if 2 identical tanks are set up side by side and everything about them is identical there will still be some differences. Water chemistry is ever changing and there are many things that contribute to what happens in any given tank.
An easy temp QT set up can be done using water directly from the main tank during a water change. Instead of the old main tank water being thrown out it can be used to fill the QT by 1/2 to 3/4 of the way, then finish with clean water which serves as a water change on the QT tank. This is the best way to match water conditions in the main tank, especially when moving sick fish from main tank to QT in a hurry/emergency situation. This eliminates the need for acclimation period from main tank to QT as long as the temp is the same as the tank water when the top off of clean water is added. (this would be no different than the fish being in the main tank with a water change being performed) Please keep in mind that if the fish going into QT are newly purchased, then acclimation is still required as usual.
Live plants in a QT are not a good idea. Silk plants are a safer and easier way to go for QT alongside of rocks and other decor that can be easily and safely sterilized between uses. To preserve some of the bacteria culture from the main tank rocks can be used from the main tank to QT but should be sterilized before returning them to the main tank later. Most of my tanks hold "extra" rock work that can be borrowed for QT at any given time without upsetting the needed territories for the fish who live in these tanks, which allows me to always have a safe way to move bacteria culture to the QT tank when it is needed. Lava rock and tufa rock are both great for this as they are very porous and retain a larger bacteria culture than dense rocks such as slate, granite, etc.
While Byron mentioned that the extra live plants are not a problem if they are lost due to medications, it must be remembered that dying/dead plant matter will pollute the water and can quickly alter water chemistry in any tank. Sick fish that require medication also require very good water quality, so the live plants defeat the purpose in that kind of situation and can make a problem worse, as well as can contribute to turning a safe medication into a toxic mess. Most medications react to any amount of ammonia or nitrite in the tank as well as high nitrate, which is why it's important to always test water before using any medication. By setting up the QT with the main tank water and using clean water as a water change this helps to ensure that water quality is good from the very start, however, it should still be tested just to be sure.
QT tanks are also usually best kept bare bottom which makes them easier to clean and eliminates the need for replacing or sterilizing any substrate after a medical treatment or exposure to disease, illness, parasites, etc. If substrate is used it should be sterilizes between uses, especially if medications were previously used in the tank. Some medications can leave residue behind and not all medications are safe to mix, as well as not all medications are safe for all animals. Again, if seeding of the QT tank is needed or desired, a nylon stocking filled with gravel from the main tank can easily be used and put into the filter box or set into the tank of a QT. This makes it easy to remove when the QT tank is no longer needed or when things need to be cleaned/sterilized before the next use, and it can be easily removed before medicating to save the substrate for future use.
When it comes to selecting the size of QT tank needed, the largest fish in the tank (or planned to go into the tank) should be taken into account at their adult size, even if they are not yet at adult size. This prevents the need to purchase a larger tank later for use when the fish are adult. In this situation a 40 breeder or 55 gallon tank should be seen as the minimum tank size for QT due to the adult size of angelfish and farlowella.
So basic steps in order for setting up a QT tank are as follows:
1. Clean/rinse the tank (between uses it can be cleaned with bleach water and allowed to air dry before storage which is a safe way to sterilize after use)
2. Add water from main tank to accommodate 1/2 to 2/3 of the volume of the QT.
3. Add heater and set to match that of the main tank (unless a warmer temp is needed during QT)
4. Top off QT tank with clean water (this is the "water change" to help ensure good water quality)
5. Install filter. HOB filters work well for this because they allow for carbon to easily be inserted at the end of treatment or to be used during situations using medicated food)
6. Add decor. Silk plants, rock, or pvc tubes (be sure the pvc is large enough for the largest fish to easily swim through at all times)
7. Add thermometer. (I choose to use a floating thermometer for QT tanks because they are easy to move from tank to tank as needed and are more accurate than stick on thermometers)
8. Test water for ammonia, nitrite, and nitrate.
9. Add fish as soon as temperature is appropriate.
Setting up a temporary QT in this manner also makes things quite easy for break down and storage when it's not in use. When QT is no longer needed simply add bleach and let the tank run with bleach water in it for 24 - 48 hrs. At the end of bleaching period empty, rinse everything very well and let stand to air dry for a few days. Once everything is completely air dry all of the equipment can then be left in the tank to store dry until it is needed again.
I hope this all helps. If anyone needs clarification please ask.