Byron requested I stop back in on this thread and give my input regarding the bacterial infection and if I believe it to be related to the acclimation procedure... and no, I do not believe the acclimation process to be a factor, or the time spent in the bag.
The bacterial infection such as I saw in your photos appears to be in an advanced stage, which is likely why it killed the fish so quickly. While these infections surely are contagious to other fish, unless the other fish show any type of symptoms, I would not suggest medicating the main tank. The other 2 fish that died may also have suffered with the same infection but it sounds as if they were more in the early stages. Where on the fish the bacteria attack and progress, how stressed a fish is at the time, changes in conditions (which cause stress) and even simple things such as water temp will all play a role in how fast the bacteria progresses and how well the fish is able to fight off the infection. The other thing to remember for future reference is that diet also plays a huge role in fish disease/illness issues. There are a great many aquarium fish out there that are receiving plenty of food, but not proper nutrition, which will weaken the fish's immune system.
It is very likely these fish were infected at the time you purchased them, so its important to inspect new fish very carefully before spending your money or attempting to take them home. If there is 1 fish in a store tank that appears sick, then you don't want to buy any fish from that tank. Fish disease/illness tends to spread quickly, and any animals sharing the same water will be exposed. As was already mentioned in this thread, all new fish should first spend at least 2 wks in a quarantine tank before going into a main tank. This time in quarantine gives you the chance to monitor the fish's health and to do any medicating in a safer (and less expensive) manner. It is cheaper to medicate 5, 10, or even 15 gallons of water vs medicating 90 gallons. Because not all medications are safe for all fish, this also eliminates the problems of what meds to use without wiping out healthy fish, especially those of other species.
Can you describe how you went about the acclimation process? 45 minutes of acclimation, if done properly, should be more than enough time for a gourami, and if the water parameters from the store were close to that of the home tank, I would call 45 minutes a bit long...
When acclimating fish, ammonia in the bag water is of course a concern, but more important is the amount of oxygen content in the bag water and how quickly and/or drastically the conditions in the bag water change. I am wondering how long they were in the bag for total length of time? (ie. from the time they were put into the bag until the time they went into the tank) One thing many people miss with concerns about acclimation is pH shift. It is an easy task to test pH in the bag water at the beginning of acclimation, and at the same time testing pH in the tank water. If they differ greatly (more than .3 in either direction) that would call for a slower, longer acclimation procedure... but does require more frequent additions of water (in smaller amounts) during the acclimation process.
One other thing you may want to check on that will help you in the future, is to find out what type of filtration set up your lfs is using. There are a lot of different systems set up in the lfs's, and unfortunately, many of them run the same water through every tank with 1 main filtration unit... which exposes every fish in every tank to any disease or illness or parasite that 1 single fish may bring in. If you discover that your lfs uses such a filtration system, then it is even more important to wander through all of the tanks hooked up to that system and look for any fish that appears unhealthy. 1 sick fish means all others sharing that water have been exposed, thus you will want to find somewhere else to shop for fish in the future.
Store filtration and fish keeping practices overall are very different from that of a home system. Store tanks are nothing more than holding tanks, and the amount of stress fish experience in a store tank can be quite extreme, which makes them more vulnerable to illness/disease/parasite issues.
I have found that shopping for fish on the day they come into the store brings me better results than waiting until the fish has been there a few days or longer. While many people reason that waiting will offer a quarantine period in the store tanks, this is usually not the case. If we consider what happens in those store tanks over the course of a few days, this will make more sense. Every time someone goes into the tank to catch a fish, the amount of stress they inflict on every fish in the tank is extreme. Most stores will use the same nets in all tanks without first disinfecting them, which spreads illness issues quickly, and water quality in store tanks tends to be quite poor overall, which also leaves the fish open to a huge range of problems.
The only exception to this for me is when dealing with marine animals, and then, again, only if I know the store uses proper procedures for quarantine and etc.
Shopping for fish can be a complicated process, but understanding all of the factors involved, carefully inspecting all fish in the system you are wishing to purchase from, and proper quarantine at home can help prevent problems like this in the future.
I hope this information was helpful.