Assuming your enclosure and conditions are suitable as per our Care Guide, if your spider pet has gone off its food and has suddenly become more secretive there is a good chance that it is preparing to moult (ecdysis). Spiders typically stop eating a week or so prior to moulting and will take about the same period after moulting to regain their appetite. If you suspect your spider is going to moult, do not leave live food insects in its enclosure as they can harm your spider during the vulnerable moulting process.