It is not a big bay and in the summer fills up easily; be careful at night, when the wind changes, to do not touch another boat.
The botton is sand and weed, mostly good holding, anchor in 2-10 metres where convenient without blocking the approaches for the ferry (Est side)
In the event of winds from S / SE the bay on the north side ORMOS FIKI offer a good shelter.
More info : https://en.wikipedia.org/wiki/Othoni
Weather forecast : http://www.windfinder.com/forecast/othonoi
Good shelter for the prevailing NW wind, on the W side there is a small harbour with mostly 1,5/2,5 metres depths.
Ashore there are several tavernas which often have fresh fish, and limited provisions can be obtained.
More info : https://en.wikipedia.org/wiki/Erikoussa
Weather forecast : http://www.weather.gr/gr/en/weather_Ereikoussa_14150.aspx?i=1