Fish acting weird

[Silly_Fish]

My black molly has been acting different today as he usually swims around with the other fish but he’s Been sitting in a cave all day not really doing anything, any ideas why?(my other fish are acting normal)

 

[Colin_T]

check the water quality
do a 75% water change and gravel clean the substrate.
monitor the other fish and make sure nobody is bullying it.

 

[Silly_Fish]

check the water quality
do a 75% water change and gravel clean the substrate.
monitor the other fish and make sure nobody is bullying it.

Another male has been bullying it a bit like chasing it but he’s been doing it for a while and the black molly has only just started hiding.What should I do about it?

 

[Colin_T]

separate it