I just weighed Coco. His weigh is 0.088 kg. I don't really know what that is though... Like, is that normal? Or Is he too skinny? Or is too fat?

Bird weight is usually given in grams, and that's 88 grams. That's a pretty typical weight for my flock. The weight fluctuates from day to day and season to season, but his father Pip usually weighs in the range of 87 to 93 grams, and his mother Ladybug weighs in the range of 79-82 grams. Coco's current weight is about the same as his father and more than his mother, so it's probably a good weight for him.

Sounds ok to me. Zorros weight is 130g

Zorro is a different specie.
My tiels are in the same range as Coco.
The heaviest weight of my babies (during peak weight time) was almost 130g!

Hes around 138 is full 126 if not

imagine my horror when once at the vet, assistant converted bird's weight incorrectly writing down 800g, instead of 80! and the next step was to prescribe medication, according to the weight. A good thing I was there, and I am apparently familiar with metric system much better than that assistant was.
You guys should really switch to metric. I am an engineer, and can't express how complicated everything is made!

Gl with that

actually I don't know but can only guess LOL

oooh, I got it. Is it a "good luck with it"?