Check adult requirements
Record the baseline and check year-round temperature and oxygen availability. Do not infer the aquarium's condition from a single sign. Confirm scientific identity, adult size, diet, social behaviour and swimming zone.
Then compare adult size, activity and social requirements 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 legally sourced species that do not require a pond before continuing. Keep a reference so the result can be compared. Plan the complete group and monitor feeding, breathing, injury, shelter and space use.
Do not treat “coldwater” as a list of mutually compatible fish.