9 years guppy experience, havent lost one from a pet store in a long time (maybe one or two out of ten)
Some things that may help a little.
First and foremost, find out the day they get their trucks full of fish in. It may seem to some that it "increases" stress to go from farm, to wholesaler, to fish store, to your house. But in my opinion, going from petstore to house in a bag for 5 minutes and directly into water that is almost identical to the store (same city, same water) is not stressful on them. Most importantly, it dosent give whatever nasty bugs are floating around their community tanks a chance to attack the new guppies.
If you plan on getting serious about raising guppies, some things will help.
Dont overfeed new fish. They only need food 1x a day, 2 at most. Only a tiny pinch. In nature they graze on low quality food that is mostly moisture, the rich protein vitamin food that we feed them would be like eating a steak dinner with veggies 3 times a day. That is not necessary, even tho they can eat and clear their bowls quite alot. Pregnant females and growing babies are the only fish that need lots of food. I suggest just keeping males, all of good quality. Mine are all the same color. It makes a good display in a nicely setup planted aquarium.
Salt. If you don't have live plants, go ahead heap in the AQ salt. Many Guppies and molies are raised with some salinity, or at least they use to be.
Turning up the heat to 82 and adding a good deal of aquarium salt can help them build up a slime coat. You can use marine salt, which will work even better, but has to be dissolved first in a bucket then top off the tank.
Quarantine if possible, especially if you have several diffrent tanks.
If you have a bare bottom ten gallon tank,you could try a product like methylene blue, very cheap stuff, to make sure there are no bacterial infections or fungus/ick for a few days or a week.
You can also use something like prazipro to de-worm and de-internal parasite the fish.
The worst types of bugs are the kind that attack the stomach, eventually destroying the gut so much the fish dies, while no outward symptoms are ovbious. These worms called "callamanus" are the scourage of the guppy raiser, will quickly go thru and wipe out an entire fishroom if not noticed. Read up on them, and fear them. Early on, they can be stopped by de-worming a fish, but once they have grown and spread, they are impacted to the stomach so much that the fish cannot pass, and dies. A few drops of water or a dirty net, or bucket, or siphon tube, with one tank of guppies or mollies infected with callamanus, can wipe out hundreds of guppies. Its very contagious, and practially unstoppable given enough time passes before you notice them.
In my experience, guppies are not very suseptible to ick.
So if you see what im doing here, putting into a bare bottom tank with just a heater and airstone, using medication like a methylene blue, and using heaps of AQ salt, extra slime coat medication, and setting the heater to 82f degrees,starving them for a day....Basically your cranking up their metabolizm and immune system turning them into overdrive mode and they will usually quickly perk up act healthy and get over whatever minor problems they will have gotten from the long journey
API makes a meciation called "general cure" which is a internal paracide mixed with a dewormer. Should clean them out.
This also should be seriously considered in the Q. tank, since worms and internal problems are the worst thing you have to worry about
Just make sure you dont combine medications that are not suppose to be combined.
Matching PH is also important. Tho not that much. Tanks that have low buffering capacity and high bioload such as a planted tank that has not had a water change in awhile, can drop the PH quite abit.
I do not worry about the drip acclimation method, you dont have to baby fish so much. I dont even worry about floating the bag, just come home cut it open and dump them in. Whatever. If you want to pour the bag over a bowl and let them fall into a big net, go for it. I just dont worry about it.
Most guys that send guppies to shows de-worm them on a regular basis.
