Foxface and eel strange behavior

So today my snowflake eel swam almost up to my foxface and he began to rubbed against the eel. After a few seconds the foxface moved and the eel followed the eel then almost jumped and rubbed the foxface again and the foxface did not move. The eel then moved again and the foxface followed and they both rest again.I am not sure what is going on I do not think it is fighting because I feel the foxface would be ruining from the eel not rubbing him and the eel would bite the foxface and would be much more violent. I know my eel likes to be rubbed he will sometime rub himself against the shrimp I feed him. So perhaps they are using each other as rub mats or being friendly? I dont really know any suggestions to what is going on is much appreciated thanks.