A simple solution would be to add plants and or shale to the tank. A lot of fish are territorial and also need hiding places. Is it a Blue Gourami?

Could you please list all types of fish. First for start up tank way to many fish to cycle the tank which caused spikes in nitrates/nitrites. Please look up cycling - here is one site.

http://faq.thekrib.com/begin-cycling.html

This is all too complicated for me (never did it as a kid, but then back in 60's onward the Dr. Innes books I read informed one to set up the tank, planted, for about one month allowing it to 'mature' and add fish slowly - so same thing.)

I do it now by setting up tank, letting it sit for a bit then gradually add fish (two to three to begin with) until filter floss, gravel et al cultures bacteria. (To speed this up I keep two filters per tank - 20 long, and use filter from established tank to start new one, takes a day! (sand, floss, from an established tank does the same or viable bio bugs can help)

Again, sounds overstocked from the get go, and need to know tank mates. Gouramis are extremely territorial (regardless of what you may read, for the MOST part, there are exceptions). I have kept several types and eventually as they mature they get agressive about others in 'their' space.

In this size tank one is enough depending on type. And tank mates must be choosen carefully as well. Need live plants (like to eat plant matter) and for cover as well.

Overfeeding won't help as you know but especially harmful when setting up a new tank.

You didn't need the chemicals, (pet store makes money) but water changes to keep levels low, and again starting out on right foot (or is it the left, lol)...

Please list all fish ok. Best Sherry

PS. I had bought new larger tanks for the different gouramis (four dwarf reds and dwarf blues in seperate tanks). With wood, heaving planted and over head plants, lower light and at first they each took their part of the tank, but eventually both times dominate male picked weakest to death, (took him out but stress killed him).

They also had viral diseases from source so illness cropped up fast. I had go give all but one each tank away as I could not add that many more tanks! Tried with second and same thing. More research (I had done so) and paid more attention to the fact that when they mature they need tons more space.

The one that is left is in a huge round globe (about 30 - 40 gallons) and it houses a school of priscella tetras and black neons - they are both too fast and confuse him as a group so he basically leaves them alone. Prior to that he (and others before him) would pick on cory cats, bettas any other fish in with him/her. Now I have two female bettas, who sparred off for a few hours and now leave each other alone, the one gourami, school and cories. Gourami and all are ok. But it was not original plan of three/four in a beautiful tank setting. Was beautiful while it lasted (about two weeks, lol)...

I resited the temptation when I bought the moonlight gourami and only purchased one. He/she is in with a school of blue neon? rainbow fish (five can't find anymore but put mirror at end of tank to fool them a bit ie larger shcool) and small school of asian glass catfish. All get along. Did have the female long finned betta but to my suprise the rainbows chomped her fins... You never know!