Grow-out tank management

Purpose

Raise juveniles safely to the next stage

Main pressures

Food, waste, oxygen and size differences

Best tool

Frequent observation and records

Critical decision

When to split the group

Difficulty

Intermediate

Design for cleaning and observation

Use mature filtration, accessible bottoms, guarded intakes and enough surface movement. A complex display layout can hide dead fry and trapped food. Grow-out tanks should be easy to inspect and maintain.

Feed frequently without creating a waste system

Small juveniles may need several meals, but every feed must be matched by removal, filtration and water changes. Spread food so dominant fish cannot control one location.

Grade by size before bullying or starvation appears

Size differences compound because larger juveniles reach food first. Split groups when a clear gap develops. Use gentle handling and avoid grading so often that stress outweighs the benefit.

Use behaviour and water quality to set density

There is no universal fish-per-litre rule. Watch oxygen demand, growth rate, fin condition, feeding access, ammonia, nitrite and nitrate trends. If maintenance is becoming extreme, the tank is already telling you density is too high.

What to record

Record stocking count, age, average size, feed type, meals per day, water changes, test results, deaths and every split. Compare growth and survival between batches instead of relying on memory.