Skibbe took charge over the winter break for Markus Babbel, but was sacked
after losing all five of his games in charge in all competitions.
Tretschok and Covic combined to feature in 157 matches for Hertha during their
playing days, and both have been promoted from roles within Hertha's youth
The club is looking for a permanent replacement for Skibbe, but the duo will
take charge of Saturday's home match against Borussia Dortmund until a new man
can be found.
Hertha is in 15th place in the league and only two points above the drop zone.