I hav ehad mine for a month. I had to cut out the bottom of a 2 liter soda bottle and place that around them a t chow time. Then I put a small piece of "cyclopeeze" food in the bottle. After it melts, i blow the waer around in the bottle with a baster to keep the food suspended and moving. Somewhere during this, the polyps will expand.
After an hour or so, the polyps close up.