HELP! my Flowerhorn is darkening and vibrates/shivers

[Ace Ringo Dakz]

My flowerhorn is about 3 inches now. It will be 3 months old this coming Nov. 10.
I transferred it to a bigger tank two weeks ago. Since then, its color turns darker and darker everyday. He is very aggressive though as always. Eats a lot as always. And plays around the tank (goes up and down and swims fast) as always.
But the problem is my FH darkened and is vibrating/shivering at times and it is head standing sometimes.

The tank my FH is in now is divided into two. There is a bigger FH in the other side of the tank.
They were feed before with Humpy Head. But last Friday, I started feeding them with OceanFree Super Red Syn. Their nuchal hump improve/grow when I started feeding them with SRS. But my FH color is still dark and vibrating/shivering and head standing sometimes.

Could my FH be sick? What is its illness? How can it be cured? PLEASE HELP! I need advice guys...

*Tank size is 36x18x16. Weekly water change. Using 5in1 Water Pump Filter.
*The section that my FH is in is 1/3 of the tank size.

 

[ECW]

It looks heathy. But really stressed. Those dark bars are stress bars. It may be female? Getting ready to lay eggs?

 

[Ace Ringo Dakz]

It looks heathy. But really stressed. Those dark bars are stress bars. It may be female? Getting ready to lay eggs?

It is a male.

 

[Ace Ringo Dakz]

It looks heathy. But really stressed. Those dark bars are stress bars. It may be female? Getting ready to lay eggs?

Is it a fader? I wonder.
My FH is very aggressive and eating a lot.

 

[ECW]

If it's a male. It seems like he's stressed. Try blacking out the divider/blocking their view of each other. The other flowerhorn on the other side looks significantly bigger. Head standing is a sign of being afraid. The shaking can be a sign of wanting to mate. Lol. Your fish is confused. He's just trying to figure out where he stands as far as dominance.

 

[Deadliestviper7]

U need decor/plants for him to feel safe.

 

[Ace Ringo Dakz]

If it's a male. It seems like he's stressed. Try blacking out the divider/blocking their view of each other. The other flowerhorn on the other side looks significantly bigger. Head standing is a sign of being afraid. The shaking can be a sign of wanting to mate. Lol. Your fish is confused. He's just trying to figure out where he stands as far as dominance.

Okay will try that.

 

[Ace Ringo Dakz]

U need decor/plants for him to feel safe.

It eats the plant. I just placed a background filled with plants on one side of the tank.

 

[ECW]

U need decor/plants for him to feel safe.

Good idea. Put a ceramic pot in there or some kind of cover for him as well as blocking them from seeing each other should do the trick. It's stressful and unhealthy for them to always have to see each other and display for dominance. Imagine if you had to live in a condo with your enemy/someone you hate.

 

[Aquanero]

Looks to me like it wants to breed with the other flowerhorn.