I've been keeping a pair of Apistogramma Ortegai for a month and a half now and over the past few weeks I've noticed a change in behaviour in the male, namely increased shyness, muted colours, and significantly less time spent moving around the tank. I'm doubtful this has to do with water chemistry or aggression, as none of the other fish have any problems and the female of the pair has become very outgoing and frequents all corners of the tank. Previously the male was much more active and he would swim about and even do the mating dance in the open area.
I'm mainly asking this because most recently I found him wedged face first in a hollow in a wood piece, as seen in the following images:


I've also seen him hang motionless in this location for hours at a time while not even interacting with the other inhabitants in the tank.

Images from the beginning:



The tank is a 20g long with substrate mix of fluval stratum, ADA amazonia and pool filter sand. pH is 7.2 and there is plenty of wood and dead leaves for tannins. Temp is about 24°C and light is on for 8 hours a day.
Other inhabitants include 6 diamond tetras, 1 female Ortegai, 1 Sturisomatichthys Leightoni, 1 Rubber lip pleco, and two amano shrimps.
All thoughts and opinions are appreciated greatly
I'm mainly asking this because most recently I found him wedged face first in a hollow in a wood piece, as seen in the following images:


I've also seen him hang motionless in this location for hours at a time while not even interacting with the other inhabitants in the tank.

Images from the beginning:



The tank is a 20g long with substrate mix of fluval stratum, ADA amazonia and pool filter sand. pH is 7.2 and there is plenty of wood and dead leaves for tannins. Temp is about 24°C and light is on for 8 hours a day.
Other inhabitants include 6 diamond tetras, 1 female Ortegai, 1 Sturisomatichthys Leightoni, 1 Rubber lip pleco, and two amano shrimps.
All thoughts and opinions are appreciated greatly