To me it sounds like he is stressed because he has been put in a very new tank. 'Established' BTW, means a tank that has been running for 6 months. A cycled tank is one that has been running for 6 weeks or more. Any tank younger than 6 weeks should actualy be running with either only a few hardy fish or should have been fishless cycled beforehand.
Dwarf gouramies are not very hardy and can easily catch all sorts of diseases and their health will deteriorate quickly and the result will be death.
Your tank does not sound like it has cycled. So, firstly, stop adding any more fish.
Next,r ead through the links in my signature. They should explain teh cycling process and the importance of maintainance and of a test kit - get one ASAP!!!
Cycling is the process by which fish waste is broken down and converted to less dangerous substances.
You see fish waste contains ammonia. Ammonia is lethal and can kill fish even in very small amounts - after about one week, a new tank will get what is called an 'ammonia spike'. The ammonia at this point is at its highest and at its most deadly. Unfortunately, this is also the time when you added the gourami...
Luckily though, at about this time, you also start to get good bacteria growing in your filter's media and gravel. These bacteria change the ammonia to the slightly less toxic nitrIte. NitrIte is still very poisonous though.
Eventualy, more good bacteria will grow which use up nitrItes and change them to nitrAtes. NitrAtes then need to be removed manualy by doing a weekly 25% water change with de-chlorinated water.
Chlorine in tap water, BTW, is not just irritating for fish, it also kills the good bacteria. So make sure you NEVER use water containing chlorine to rinse out your filter media (when it gets clogged) or for water changes. Use old tankw ater to clean out the filter (only when necessary) and make sure you use de-chlorinator on any water that will be going into your tank. Also, if you find you ever need to replace any filter media, change bits of it at a time or you will get another ammonia and nitrIte spike as the tank will 're-cycle' when you remove all the bacteria (when you take out the media).
Something else you need to consider is that tiger barbs should be in groups of at least 7 (or they will nip), all schooling tetras like the ones you have should be in groups of at least 6 and rainbow/albino/red-tailed sharks should always be kept alone. Alternatively, you can try a group of 6 or more. 4 is too few realy. Then there's the loach which needs at elast 2 more companions.
My advice to you is to do daily water changes of about 50% daily until you have a test kit and can accurately monitor your water. Then, once you see that ammonia and nitrIte are at ZERO, start doing just one weekly water change as there is no need for any more than that once the tank is cycled (which it is once ammonia/nitrIte are no longer detectable). At this point, if you still have both sharks, add another 4 (add a couple more albinos and a couple more rainbows). If you can persuade your other half, getting rid of one (return it to the LFS) is actualy a better option. Then, a month or so later, if you still have neons left, add enough to make it a group of 6, and if you still have tiger barbs left, add enough to have a group of 7. Then, if your clown loach is still alive, get 2 more (as the tank you were going to buy is big enough).
I have to say that the chances of a lot of the fish you have to survive a cycle are slim. Neons and dwarf gouramies should only be added to established tanks. Clown loaches are prone to ich when kept in poor conditions. Tiger barbs don't do well in water with fluctuating parameters - that includes the ups and downs of the cycle's spikes, the sudden nitrAte increase at the end and any temperature fluctuations (which you WILL have during the night and in winter - get a heater with a built-in thermostat). The sharks are more ressiliant but with the two in the tank, one will probably end up killing the other if you don't intervene.
Now to make something clear, I don't want you to panic. There is realy nothing you can do for the next month or so but do lots of daily water changes and test your water regularly to keep track of the cycle.
A note on the test kit - don't get the strips - they are innacurate and get worse with age - get liquid-based tests. They are great.
Also, don't over-feed. Once a day - just enough for all the fish to get a mouthful, is fine while the tank si still cycling. You can increase the amount in about a months time if you feel it's necessary.
Add some plants - and especialy any fast-growing floating species. They will both provide cover and use up some of the ammonia and nitrAtes etc in your tank.
Something else you can do to speed up the cycle is get some filter media right out of one of your LFS's healthiest (freshwater) tanks. The media will help kick-start the good bacteria colony in your tank and will speed up the cycle incredibly. You may even get an instant cycle and be able to save all your fish. If the LFS won't let you have used filter media right from inside their tanks, ask for a little bit of the gravel instead. This also contains good bactria and will also help (though not quite as well). If it's necessary, it is actualy worth paying them for some of their media. Make sure the tank you get it from looks healthy - no dead or apparently sick fish - and make sure you put the media into your tank immediately once you get it home - if it dries out or is left in an empty tank for too long, all the bacteria will die. Also, don't rinse it in tap water! The chlorine will kill the bacteria and that pretty much alliminates the purpose.
Good luck, welcome to the forum...
/www.skepticalaquarist.com/docs/behavior/otherbe.shtml 
Depending on the size of your mothers tank he could go in with platties, but if the tank is anymore smaller than your own i wouldnt bother.
