Social media channels, particularly Twitter/X, played a significant role as information platforms during the COVID-19 pandemic. As journalists are crucial actors on that platform, an analysis of the content and tone of their tweets during the pandemic can reveal the role they played in shaping public understanding of this public health crisis. Our analysis focuses on Germany where the government enforced relatively strict anti-COVID-19 measures and where strong opposition to these measures emerged outside the mainstream media. We analyzed almost 10.000 tweets of 247 journalists of mainstream media during a 14-month-period. To shed light on journalists' watchdog versus collaborative role orientation, computational methods were used to extract themes and tone in their pandemic-related tweets. Furthermore, network analysis was utilized to identify influential actors in journalists' interactions with experts and other users on Twitter. The findings revealed that journalists tweeted most about topics like the economy, protests, and Chancellor Merkel's ability to implement a restrictive containment policy. As demonstrated by the network analysis, journalists frequently interacted with cabinet members and pro-government experts on Twitter during the pandemic. The analysis also revealed that some tweets were characterized by an anti-protest and anti-lockdown tone, but these came from different groups of journalists.