Hello, I have a problem with a graph I'm trying to do. Every time I try to produce it, it gives me this error: time_trans works with objects of class posixct only.
The code is as follows:

And the formatting is this one:
fish$Datetime <- strptime(paste(fish$ï..Date,fish$Time ,sep = ""),format = "%Y.%m.%d %H:%M:%S",tz="GMT")