The name has several variations but the origins are one of the oldest in Europe and can be traced to 186CE to its first mention in the Franco-Roman Census found near Jagsthausen.
The ancient hamlet of Olnhausen, Germany near Heilbronn is still in existence.
Several Ohlhausen family crests bear a house and eels.
Ael/ahl/ohl are all Germanic etymological variations of the English word "eel".
Variations of the name: Olnhausen, Ohlhausen, Olhausen, Aelhausen, etc.