Sick Gourami - Lost Colour, Not Active

[Tropical911]

Tank size: 350LTR
pH: 7.36 (calibrated digital tester)
ammonia: Ran out of test strips
nitrite: Ran out of test strips
nitrate: Ran out of test strips
kH: Ran out of test strips
gH: Ran out of test strips
tank temp: 27c
Tank Age: 6 months
Filter type: TetraTec 1200 External

Fish Symptoms (include full description including lesion, color, location, fish behavior):

Fish is just sitting about, not moving much. Seems to have lost its colour. Constantly keeping its feelers towards the front of its body. Floating around lifelessly, just moving its feelers around.

Thanks in Advance For The Help

Volume and Frequency of water changes:

20% Every Week

Chemical Additives or Media in your tank:

None.

Tank inhabitants:

6 Mollies
6 Plattys
6 Corrys
9 Neons
1 Plec
4 Gouramies
2 Angel Fish

Recent additions to your tank (living or decoration):

None

Exposure to chemicals:

Nope

Digital photo (include if possible):

Will post.

 

[WILDER]

Its hard to say what going off without water stats as thats the first thing you look at.
Gouramis are quite prone to bacterial infections the signs are being pale or darker in colour, being listless and lethagic and sometimes not eating.