Table 1. The differential response of exposure to acid pH is niche-dependant.

Sampling	Variable	p-value Skin mucus	p-value Feces	p-value Water
T0	Biological replicate	1	N/A	N/A
	Tank	0.0441*	1	N/A
	Treatment	0.1623	0.4	N/A
T1	Biological replicate	1	N/A	N/A
	Tank	0.0002***	1	1
	Treatment	0.00009999***	0.001389**	0.1
T2	Biological replicate	1	N/A	N/A
	Tank	0.1147	1	1
	Treatment	0.0494*	0.3014	0.001389**

P-values from PERMANOVA highlight the effect of the variables: “Biological replicate” (groups of 4 fish in the same tank), “Tank” and “Treatment” (acid stress or control) on bacterial communities in three ecological niches (skin mucus, feces and water) at three sampling times. P-values in green are < 0.05. No data is available for feces and water samples for biological replicate, because only one sample was taken in each tank. No data is available for water at T0 because only one sample was taken for the whole system.