How an insulated fish box holds temperature
A plastic fish box manufacturer supplies the cold chain with insulated containers that keep catch cold from the quay to the processor. The workhorse design is a seamless, double-wall HDPE seafood tub: two rotationally moulded walls with a polyurethane foam core injected between them. Because the shell is rotomolded as one piece there are no weld lines to leak, and the foam core slows heat transfer enough that a box loaded with ice holds useful temperature through a shift on a warm deck.
Buyers usually meet the category through the big 600 to 1,000 litre bulk boxes used by processors, but the same construction scales down to 50 litre tubs for boats and retail counters. An insulated fish box is specified by three numbers together: internal volume, external footprint and insulation thickness.
Capacities and footprints
- 50 to 120 L. Boat and market tubs around 540 x 320 x 350 mm, sized for one person to lift and for retail display.
- 260 to 320 L. Mid-size plant bins in the footprint class made popular by Nordic insulated containers, roughly 1,090 x 560 x 660 mm including lid.
- 600 to 700 L. Bulk seafood tubs around 1,230 x 1,030 x 820 mm at about 60 kg empty, the standard unit for cold stores and transport.
- 1,000 L. Deep-body boxes for processors that need volume without stepping up to a fixed cold room.
A rotomolded fish box in the 600 L class weighs 55 to 65 kg empty and carries about 4 tonnes static with a dynamic rating near 1 tonne, so loaded boxes stack several high. Forklift channels and side handles are moulded in, and most designs add a drain plug with built-in stopper storage.
Food contact and daily hygiene
The resin matters more than the colour. Specify food-grade HDPE with UV stabiliser, and ask for the food contact test route your destination market expects rather than a generic food safe claim. Our guide to food contact compliance explains the FDA and LFGB routes most exporters meet first. Smooth walls, rounded corners and a drainable base keep wash-down quick when the same insulated container moves between raw and processed zones.
What to confirm with a plastic fish box manufacturer
- Resin grade and food contact documentation for the inner surface, not just the outer shell.
- Foam type and thickness, plus a cold-retention figure for your ambient conditions and ice ratio.
- Drop and stack tests at low temperature, where thin-wall mouldings are most likely to crack.
- Lid design and latch type, and whether lids are included in the quoted price or added separately.
- Container loading quantity per 20GP and 40HQ for landed-cost calculations.
Colour, logo, drain position and lid styling are routine customisation, and tooling for a new footprint takes weeks, not months. Start in the plastic products catalogue, compare factories through the company directory, and read our factory audit checklist before placing a trial order.
Related product categories
The materials and part types discussed above are grouped in our sourcing directory:
