How much flake food is too much?

[ZakREEF]

I feed my diamond goby about one thumbnail size flake. I feed by mixing the flake with 5ml of water, I then mix it until it breaks down and then suck it up with a large syringe. When I put the syringe/pipette next to the diamond goby he just latches his mouth on the the syringe and then I out small bits of food into his mouth. I feed the rest of the food to my clownfish once he becomes disinterested however sometimes I have to net out the food because other wise it will just rot. I let the guy sand sift for the rest of the food throughout the day if it is still hungry

Here's my question:
How much is too much food. Is one thumbnail flake too much for one fish?
It always seems like there is LOADS of uneaten food once I'm done( I've only fed him twice in the past week because he has been hiding)

 

[Potatohead]

Feed what your fish will eat in 30 - 45 seconds... That's all they need. If you feed more often than twice a day, more like what they will eat in 20 seconds.

 

[ZakREEF]

I feed twice a day early morning at 7am and afternoon/ evening at 5pm. Would you suggest I cut back on the feeding if there is lots of uneaten food, or will the goby just eat the food later in the day?

 

[Sk8r]

Cut back. Feed while you can watch same. Your goby will appreciate clean water even more than an excess of snacks.