Imac running Catalina. My fusion drive has three icons. Does this need to be fixed?

Ok, thanks for the screenshot. What appears to have happened is that a duplicate volume "Macintosh HD 1 - Data" was created within the disk 2's APFS Container (aka, partition) on your Fusion's HDD. With APFS, using the Disk Utility, you can delete this duplicate volume to regain space within the Container. However, BEFORE doing so, it is highly recommended that your first backup your system in case you need to do a restore later.

Ref:

• Disk Utility User Guide - Apple Support
• Using the Disk Utility in macOS - Lifewire

Would you please provide a screen shot to help us understand what you are seeing?