Summarize the following:
There might have been bug eggs in the soil or on your plants. If you notice anything crawling around inside, let it out and then reseal your ecosystem. If algae or fungus grows on the sides of the glass, you can easily clean it off. Use a piece of soft cloth or a cotton ball to wipe it away so you can clearly see through the glass.

Summary:
Remove bugs if you see any. Clear out algae and fungus regularly.