Holy Carp

The iconic fish is beloved for its convenience, charm and dropping functionality. However, like all single-use plastics, there is a misalignment between the durability and longevity of the material and the short intended lifespan of the product. The fish are used for just a few seconds, but remain for centuries, easily become litter, harm marine life, and fragment into microplastics that can end up back in the sushi we eat. The design challenge was to create a single-use alternative that matches the charm and performance of the iconic fish, without ongoing environmental harm, and in compliance with single-use plastic bans.

Holy Carp is a moulded plant fibre container with a diaphragmatic lid. The lid features a small hole, allowing the container to function as a soy dropper. The key breakthrough that enabled this design was switching to filling containers in-store, rather than a facility far from the point of use. Changing to this model eliminates the need for long lasting, potentially harmful materials, plastic linings or coatings and enables the use of compostable plant fibre material. This model has been successfully tested in venues in Hobart, Tasmania, where a plastic ban has been in effect since 2020.

The design responds to increasing concern about single-use plastic’s impact on the environment. These concerns have led to single-use plastic bans targeting the soy fish, already in effect in Hobart and South Australia, and announced in other jurisdictions like New South Wales by 2030. By replacing the beloved design with a plastic-free, home compostable and ban-compliant alternative, the design meets both consumer and commercial needs in a more sustainable material. The design is intentionally playful, and aims to protect a cultural icon, giving both consumers and businesses a positive and respectful introduction to plastic-free alternatives.

Material Holy Carp is made from moulded plant fibre, including bagasse, a reclaimed agricultural waste product. A food-safe, plastic-free and non-PFAS additive is added to the pulp to increase moisture resistance. Performance needs are met without requiring a plastic lining, aqueous coating or PFAS additives through the adoption of in-store filling. In-store filling improves product freshness and gives venues and consumers added choice. DurabilityShort term use is intentional and embraced. The material holds soy sauce indefinitely without leaking, but it is recommended to use within 48 hours for freshness. CompostabilityThe plant fibre material breaks down quickly in home composting conditions. Certification to AS 5810 Home compostability is underway. LidThe lid is reminiscent of a fish, and features a diaphragmatic shape and small hole, functioning as a dropper when squeezed. The domed “belly” area mimics the familiar feel of a traditional plastic soy fish. The tail fin is functional, assisting with opening the container, and adds a playful touch. CupA flanged edge ensures a secure, leak-proof seal. A mesh-textured underside creates friction for gripping.Fill lines indicate a 4mL and 8mL serving of soy sauce, around 2-3 times more soy than a typical plastic soy fish.