Aggressive Gourami

[Meeresstille]

Looks like quite a busy tank. Even though these are all peaceful fish maybe your gourami is stressed out by all this activity? Just a guess though and I don't know if removing any of them would help!
 
But looking at it from the stocking side of things you kind of have a generous amount of fish for your size tank with a dozen Pygmy Cories, the three Gobies and the 5 Amano Shrimp mostly keeping the bottom active, and the dozen Rummynose Tetras and the dozen Celestial Pearls keeping the mid-level active, 4 Nerites that are nowhere specific.
 
Again, I don't know if the problem is the stocking, and hopefully someone else can weigh in on that!
Just to give you an idea I have a 40 gallon, 48 inch long tank stocked with 2 male honey gourami, 12 Harlequin Rasboras, 8 Kuhli Loaches, 35 to 40 Red Cherry Shrimp and an Assassin Snail that has had a whole bunch of babies. I am concerned that I have too many creatures in my tank and am going to hand off some shrimp and some assassin snails through my local aquatic club as soon as I can.

 

[l_l_l]

Most of people I've spoken with told me it was the Gourami itself that is just being a "dominant male".
 
I removed him from the tank and now everybody's doing fine now.

 

[DreamertK]

Again, I don't know if the problem is the stocking, and hopefully someone else can weigh in on that!
Just to give you an idea I have a 40 gallon, 48 inch long tank stocked with 2 male honey gourami, 12 Harlequin Rasboras, 8 Kuhli Loaches, 35 to 40 Red Cherry Shrimp and an Assassin Snail that has had a whole bunch of babies. I am concerned that I have too many creatures in my tank and am going to hand off some shrimp and some assassin snails through my local aquatic club as soon as I can.

They say that loaches follow a different set of rules, and of course shrimps and snails dont contribute too much to the bioload. I'd probably hazard a guess that you're understocked which is good. It's up to you though, measure how much NO3 you have at the end of the week and see how much it's gone up compared to the tap. I would say to see how often you should do a WC though my understocked tank is planted and maxes out at 5ppm of NO3, but I should still do weekly WC for all the fish hormones in the water.

 

[AeonMapa]

My dwarf gourami is quite aggressive too. He will bully my rams and other fish, although I notice he never really damage them or push them to the point of stress, he just keeps them away from his floating plant nest. Maybe if you create a definite territory for him by tying a lot of floating plants to one corner of the tank, he'll concentrate on defending that rather than claiming the whole surface level

 

[Meeresstille]

 

Again, I don't know if the problem is the stocking, and hopefully someone else can weigh in on that!
Just to give you an idea I have a 40 gallon, 48 inch long tank stocked with 2 male honey gourami, 12 Harlequin Rasboras, 8 Kuhli Loaches, 35 to 40 Red Cherry Shrimp and an Assassin Snail that has had a whole bunch of babies. I am concerned that I have too many creatures in my tank and am going to hand off some shrimp and some assassin snails through my local aquatic club as soon as I can.

They say that loaches follow a different set of rules, and of course shrimps and snails dont contribute too much to the bioload. I'd probably hazard a guess that you're understocked which is good. It's up to you though, measure how much NO3 you have at the end of the week and see how much it's gone up compared to the tap. I would say to see how often you should do a WC though my understocked tank is planted and maxes out at 5ppm of NO3, but I should still do weekly WC for all the fish hormones in the water.
 

Thanks Dreamer, yeah, my Nitrates are usually between 5 and 10 (Nutrafin Liquid Test), and I do 40-50% water changes every 7-10 days. Looking at the tank it does not look overstocked, lol, but looking at the numbers when I list all the creatures it is a little scary!
 
I_I_I I'm glad you found a solution that worked for you!