Lonely Tiger Barb

Question
I recently "revived" my 20 gallon aquarium back to a clean state.  What fish I have survived the change.  These fish included 4 red-tail tetras and 2 tiger barbs.  These fish were also around 2 to 2 1/2 years old so they were pretty big.  However, the 2nd night in their new home, one of the tiger barbs managed to jump out of the tank and unfortunately, he died.  So now I am down to 1 barb.  Recently I brought home 2 new Dwarf Gourami's, but the lonely barb has been bullying these new tankmates.  I did some reading on tiger barbs and it recommended keeping tiger barbs in at least small schools, that if there are too few of them, they will bully other fish.  So here is my question.  Should I go get a few more tiger barbs?  I don't know that if the young barbs will get along and school with the more mature barb, and keep him away from the other tank mates.  If you think I should, can you recommend a number?  I have a 20 gallon aquarium, moderately planted with live plants.  4 matured red-tail tetras, and 2 young dwarf gouramis, plus the lonely barb.
Thanks alot!
Ben

Answer
Hi.
You are correct, Tiger Barbs, because they are aggressive, prefer to be in groups of 8 or more. Your tank is not big enough to hold that amount, so the best think to do is remove the lone barb. You should also buy a few more tetras, as they prefer to be in groups of 6 or more. You could either have the 2 Gourami's and 15 to 18 Tetras or the 2 Gourami's, 8 Tetras and 5 or 5 small Corydoras (such as Panda, Peppered, Albino or Bronze Corydoras).
Another option would be to have the Gourami's, 6 or 7 tetras, and 2 Blue Rams.
These are just some suggestions, but
I would stick to small fish for a 20 Gallon.

Also, you should never completely clean the tank. You will lose all the beneficial bacteria, and you may lose some fish. Just do 30 percent water changes every week, and clean half the filter in tank water every month or two.
You should also check your water stats regularly. Test the tank water for nitrite, ammonia and nitrate. The ammonia and nitrite should be 0.0. If not, do more frequent water changes until it is 0.0. The nitrate should be under 20ppm. Live plants will help lower it.

Good luck,
Kathryn

P.S. Feel free to ask any more questions.