I don't know what else to do to make my F8s to feel more comfortable. They don't seem to enjoying the tank, pacing in the left back corner or pacing in the front glass.
This is the tank:

I think I did a good job breaking up the lines of sight with the woods almost in the middle of the tank looking like a tree, and I piled some rocks and planted some plants (I'm waiting them to grow up).
This is the right side of the tank:

They have a lot of caves to swim through and a tall piece of wood with some vals near it.
This is the left side of the tank:

I made a big tree with some woods and piled some rocks in the background and planted some hygros in the back and some wisteria close to the left glass.
They don't swim through the decor, don't explore the hidden places and they don't hunt for food. It looks like they are always waiting for me to give them some food. Two or three times in a week, I offer them some snails... some kinda of 6 snails for each puffer (is that too much?), and I give to them some pieces of shrimp and some clams. I used to feed them everyday, skipping one day. Now, I will feed them one day and skip two days and check if it makes them to hunt for more food.
I don't know if the tank is very bright, since I have plants I used to have 85W of light to the 200L/53G tank, now I will try just two bulbs (30W) turned on, and see if they feel less stressed. I hope my plants can stand that amount of light.
I think I'll raise the salinity from 2g/L to 5g/L next weekend if it will make them feel more comfortable.
I read somewhere that pacing is a sign of boredom and when they pace they are trying to say " Let me out! I would like to be somewhere else!". So, the water parameters are:
Temp: 28°C/82,4°F
pH: 7.5
KH: 9°dH
GH: 12°dH
NH4: zero
NO2: zero
NO3: >5ppm and <15ppm
WC: 25% weekly
So, if you have any idea/hint/advice to tell me, feel free to do it because it doesn’t look like they are comfortable in my tank since they are not exploring the décor neither hunting, almost all the time resting beneath the tree or pacing up and down the glass.
Thanks for read the whole text.
