Reviewed 2026-07-192 min read

Mollies: water, adult size and social needs

The decision starts with variety and actual adult size. It must then be connected to stable mineral-rich water and source acclimation and checked against group, plant-rich diet and swimming space. Adding salt cannot fix unsuitable water and may harm tankmates.

Key points

variety and actual adult size
stable mineral-rich water and source acclimation
group, plant-rich diet and swimming space

Check adult requirements

Record the baseline and check variety and actual adult size. Do not infer the aquarium's condition from a single sign. Confirm scientific identity, adult size, diet, social behaviour and swimming zone.

Then compare stable mineral-rich water and source acclimation with livestock needs and recent changes. Look for genuine overlap in water, flow, territory and feeding throughout the year.

Assess compatibility and welfare

Adjust one variable and assess group, plant-rich diet and swimming space before continuing. Keep a reference so the result can be compared. Plan the complete group and monitor feeding, breathing, injury, shelter and space use.

Adding salt cannot fix unsuitable water and may harm tankmates.

Situation	What to do	Why
variety and actual adult size	Verify the species	Avoids decisions from trade names
stable mineral-rich water and source acclimation	Cross-check group needs	Finds lasting incompatibilities
group, plant-rich diet and swimming space	Plan and observe	Prioritises observable welfare

Check the result

After verify the species, measure or observe variety and actual adult size again with the same method. Record group, plant-rich diet and swimming space as well; if neither changes as expected, revisit the diagnosis before adding another intervention.

Sources and scope

Sources cover biology, behaviour and welfare. Check every range against the exact species, origin and observed conditions.

FishBase — Species ecology and biological data institution
Seriously Fish — Evidence-led species profiles institution