Diamond Goby very skinny

[Benoit Martin]

I have been trying to find the right amount of food to feed my tank and I am worried that I may have gone too low and starved my goby.
He acted very healthy since I've got him a few months back but now he's looking very skinny (very thin body) and would not come out of his cave for an entire day sometimes.
He's been eating this entire time when I feed the tank and he's constantly sifting sand when he's out.
I have increased feedings about 2 weeks ago but he's not getting any bigger.

Did I starve him? Is he in danger of not recovering from it?
Or, is it some other issue with him.

Other fish in the tank all look healthy and even though they eat very eagerly when I feed, I am not seeing any aggression between any of them.

 

[Willbiker]

Have you tried feeding close to him with a turkey baster? Maybe squirt some in his burrow and see if he takes.

 

[Benoit Martin]

Have you tried feeding close to him with a turkey baster? Maybe squirt some in his burrow and see if he takes.

He doesn't seem to be shy about eating and that's why I'm a little bit worried that he's not getting fatter