We I didn't realize that it was in a tank all by itself, so the trick isn't needed.I had a Mandarin, but this should work for a scooter as well....
I had one for 6 years and 5 1/2 of those years was fed mysis and cyclop-ezee only with no supplementation. I will tell you the trick for tanks that have other fish in them....This is just to make sure that the fish will get enough to eat with other fish around.
Go and by a small capers bottle, they are about an 1 1/2'' round and about 3 inches tall. I don't eat capers so I tossed them away. Once it's cleaned you can then use the jar.
Once the Mandarin/Scooter begins to eat frozen mysis or is showing some interest in it, take some tank water fill the jar up add mysis. Attach a string to the jar so you can lower it into the tank and have it rest on the bottom of the tank. I usually put it by where I seen him hanging out the most. What this does is the mysis that is in the jar cannot be eaten by other fish because the jar is to small for other fish to swim into it.
The Mandarin/scooter will eventually start swimming into the jar to get the food. They become very comfortable with it after a few time of doing it. This allows the Mandarin/scooter to eat as much as he wants for as long as he wants. I usually left it in there for a few hours then pulled the jar up out of the tank and discarded what was left if there was any.
They( My Mandarin) are very shy when it comes to feeding with super active fish around and they are not that fast as well. In the 6 years I had the fish it never once had a skinny stomach and this was in a tank with a tang, clowns, Black cap basslet and a few other goby type fish.....It really worked well for the Mandarin and he always new once the jar was lowered into the tank what that meant......Nothing to tricky but very effective in tanks with other active feeders.
It ended up dying from intestinal blockage from what I could gather by looking at it.....It ended up towards the end getting a super bloated belly for about 3 weeks. the over-sized belly disappeared and a few days later I found him at the bottom of the tank when the lights came on.....He was one of my favorite fish of all time. He would eat mysis from my hand and had no fear of me when I was doing maintenance......I say keep it or add it to you main tank if you think you might want to keep it. They are very cool and rewarding fish to keep, once you get them on frozen food...