That's not a regurge, that's a refusal.

He may be a more private snake that doesn't do well with an audience. Wait a week and offer him prey then and DON'T watch.

Also, my 300 grammers are still in six quarts. He may be one that will need to stay in a smaller tub longer. And you can use a $5 solder wand to make your holes, rather than a power drill.