hmmm good idea "Quarantine tanks".. I never had one. I would just med. the tank the day before I put the new fish in & med again for a week, to make sure all was fine.

I use to have a billion guppies in a 10 gallon tank. They were feeders for my turtle, but they ended up bredding so much that they were becomeing suicidal!!! they keptjumping out of the tank & were all over the floor. I put up a screen to save them but then they went to eating eachother.. it was crazy!! Poor turtle had a billion in his tank & never went hungry, but he just wasn't big enough his first year to keep their pop down hehehe.