Jack
Aquarium Advice Regular
If your using medication for a bacterial infection, you can feed medicated flake in the main tank. The concentration of medicine is relatively high in the flake, but pretty miniscule for the whole tank. Tetra makes Tetra Medica, which works well for bacterial infections. Of course, your fish have to be feeding for this to work.
Medications for parasites usually contain copper, which can be detrimental to plants and invertebrates (snails and such). Some fish are also sensitive to copper.
As Tankgirl stated, a hospital tank is really the best way to medicate if you are using medicines designed to saturate the water. When you're done, you can remove the fish and place in the main tank. Another positve out of doing it this way is that you avoid the staining in your main tank, that often accompanies fish medications.
Medications for parasites usually contain copper, which can be detrimental to plants and invertebrates (snails and such). Some fish are also sensitive to copper.
As Tankgirl stated, a hospital tank is really the best way to medicate if you are using medicines designed to saturate the water. When you're done, you can remove the fish and place in the main tank. Another positve out of doing it this way is that you avoid the staining in your main tank, that often accompanies fish medications.