Fancy Guppy always at the top of the tank.
 

I just setup my new tank yesterday.

Initially i performed fishless cycle for 3 days and took the water sample to petstore store to check if it was fine for the fishes. They tested it and it was fine.
On my way back home from the petstore, i got 3 guppies - 2 fancy guppy( a blue one and white spotted) and 1 red tuxedo. All males.

When i introduced them to the tank, after few mins, all were fine. They were moving around the tank. I fed them tropical flakes before going to bed and they ate fine. Somehow, one of the fancy Guppy( blue one) made frnds with Red Tuxedo and the other fancy one( with white spots) was alone.. but he was still fine. Enjoying/swimming all by himself.

The next day.. till morning - everything looked ok.. in around noon i found that the Guppy with whit spots( which was alone) is always hanging around the top of the aquarium. Other two moved together around the whole tank. I read few forums.. and changed 1/3rd of the water. Still he does not seem to do well. I know he is stressed out, and his tail is not as wide/bright as it was yesterday.

Below are the contents of my tank -

5G tank with tap water treated with conditioner, with hood and light.
pebbles,small ornament, one artificial plant, 3 large pebbles as resting area for the fishes.
Topfin filter 10i, tetra submersible 50W heater
no live plants currently - person from petstore told to add live plants after a month of adding fish so that cycle will stabilize

What must be wrong?
Is it the quality of water - not sure as i introduced fishes only after testing it and other two fishes are swimming happily.
is he lonely and feeling left out? - One or two times i saw the blue fancy just poking this poor guy if he gets in between his way.
Or anything else??

Please reply as i am feeling very sad for the sad and lonely guppy.

5g is a little small for those guppies, fish get stressed if the tank is over crowded and in this situation since there is more fish than the tank can handle it counts as over crowded.

Also are the white spots natural? becuase most guppies dont have white spots.
When i read about the guppy having whitespots the first thing i though was ICK, what it is, is alot of parisites createing white spots then they multiply and spread to other fish.

Ill show you a image of natural white spots(born with them) and ick (illness)

http://t3.gstatic.com/images?q=tbn:A...va6WrIthd0bYMQ <--------------- Clown loach with ick. Notice that The white spots are not part of the scales and seem to overlap the coulor





http://t2.gstatic.com/images?q=tbn:A...MY1HNpH6y0Yviw<---------- white spot puffer without ick. Notice how this white spot puffer has white spots that are part of the scales and are on the top of the scales





Ick is a common problem and is fatal but there is alot of medications for it.

Ick can start if:

the tank is over crowded.
the tempature is not correct.
the fish is stressed.
a fish infected it when you bought it.
adding infected water from a bag(from a fish store)
and more