Discus spinning in tight circles, Crashing into tank.

[Annunciation]

Problem

Please explain the problems with your fish. When did you notice the problems and did anything unusual happen that you think started them?

Old 55g sprung a leak, moved discus to 20g while I set up a new tank. 55g is now set up and cycled, moved discus over this morning. One discus was particularly unhappy in the 20g, kept trying to jump out (~ 7 times), dashed around the tank, and spins in tight circles. Now is covered in scratches from bumping into things in the tank and swimming behind the filter (aquaclear 110). Is it just a case of not having enough room to swim around or is there a serious underlying issue? All the other discus exhibit no symptoms.

Symptoms

Discus (juvenile) spins rapidly in circles, occasionally tries to jump out of tank and crashes into tank scratching itself.

Tank/Water
Tank size and ages, numbers and sizes of fish.

55g 1 month, 5 discus 2.5-3 in.

Water change regime (What percentage and how often).

20% every 3 days.

How long has tank been running? Is it bare bottom? If you have substrate, what type and how deep is it?

20g has 1.5 in deep gravel and has been up for months.

Do you age your water? If you do for how long and what is the ph swing.

no

Parameters and water source;
Note: Water Parameters are important in diagnosing problems within a tank. If you don't own test kits for the following information, you can purchase them, test your parameters and post this info as soon as possible.
temp 82 degrees
ph 6.8
ammonia reading 0
nitrite reading 0
nitrate reading ~10
What type of water or combinations of water sources do you use? If it is an RO/tap/well water mix, please list percentages in the mix.

Tap

Any new fish, plants or inverts added recently.

none.

Include any pictures or videos you have which shows the symptoms. If you can't add them to this post, please provide a link to them.

http://imgur.com/epVUWWj,IswCTiV

Damage from crashing around :/

[Annunciation]

http://imgur.com/epVUWWj,IswCTiV Damage from crashing around :/