Anyone know why my Duncan might be doing this ?

[gowlers321]

Any ideas would be very welcome. Thanks btw I haven't fed him in a good couple days.

 

[LiveWire]

Have you checked your water parameters and if so what are your readings?

 

[gowlers321]

Have you checked your water parameters and if so what are your readings?

Parameters:
Salinity: 1.024
Dkh: 7.5
Temp: 25.6
Nitrate: 10
Nitrite and ammonia: 0
Calcium: 360ppm
Phosphate: 0.010
pH: 8.3
Magnesium: 1300