Thinking INSIDE the box: the fish farm in ship containers


A uni­ver­si­ty spin-out com­pa­ny is offe­ring what could be the ulti­ma­te in aquacul­tu­re con­ve­ni­ence – an auto­ma­ted recir­cu­la­ting aquacul­tu­re sys­tem (RAS) fish farm housed in three inter­con­nec­ted ship­ping containers.

The com­pact RAS from SEAWATER Cubes is aimed at both freshwa­ter fish far­mers wis­hing to expand into mari­ne fish and land far­mers loo­king to diver­si­fy. Restau­ra­teurs and busi­nesses such as sushi chains loo­king for ultra-fresh fish are other poten­ti­al customers.

The Cube is desi­gned to bring mari­ne far­ming inland, allo­wing far­mers to offer sus­tainable fish grown local­ly. It takes up just 100 squa­re met­res of flo­or space and becau­se it uses a dome­stic tap water sup­p­ly it can be sited almost any­whe­re. It can pro­du­ce seven ton­nes of fish annually.


The Cube is the brain­child of SEAWATER’s mana­ging part­ners Caro­lin Acker­mann, Chris­ti­an Stein­bach and Kai Wag­ner, for­mer stu­dents at the Uni­ver­si­ty of Appli­ed Sci­en­ces (htw saar) in Saar­bru­cken, Ger­ma­ny who were employ­ed in the university’s aquacul­tu­re labo­ra­to­ry after gai­ning their degrees. After acqui­ring sub­stan­ti­al know­ledge about fish far­ming in gene­ral and about high­ly tech­ni­cal, clo­sed RAS in par­ti­cu­lar, they deci­ded to start their own com­pa­ny. Help by fun­ding from the Ger­man government’s EXIST – Trans­fer of Rese­arch pro­gram­me, they have been gro­wing sea­bass in their pro­to­ty­pe Cube sin­ce Octo­ber 2018. The fish take bet­ween eight and 12 months to reach mar­ket size of 400–500g.

Three year classes

Acker­mann told Fish Far­ming Expert: “In the farm its­elf we have three dif­fe­rent year clas­ses. They are all in one tank but are sepa­ra­ted by nets. You need one year to get the first fish and then you have fish rea­dy every four months. You put fin­ger­lings in every four months.” The next cycle will use gil­thead bream, which requi­re the same con­di­ti­ons as sea­bass. The entre­pre­neurs also plan to adjust the Cube for the far­ming of yel­low­tail king­fi­sh, black tiger prawn, red snap­per and Mala­bar grou­per. The Cube per­forms all con­trol and moni­to­ring tasks and all Cubes will be lin­ked to the company’s head­quar­ters via the inter­net. Accor­ding to its crea­tors, this enables vir­tual­ly unat­ten­ded plant ope­ra­ti­on and redu­ces the workload for the plant ope­ra­tor to an avera­ge of 1.5 hours per day. Water is fil­te­red three times an hour, and less than 1% of pro­cess water needs to be repla­ced daily.

The cost of one Cube is €250,000 (£215,000). The com­pa­ny will also pro­vi­de a pro­ces­sing unit in a fourth con­tai­ner. This cos­ts an extra €50,000 but has the capa­ci­ty to hand­le pro­duc­tion from up to five Cubes.

Fingerlings and feed

SEAWATER Cubes will also pro­vi­de fin­ger­lings, orga­nic feed, a spe­cial mix of mine­rals to give the water the same make-up as sea­wa­ter, and ever­y­thing else nee­ded for pro­duc­tion, as part of a sepa­ra­te packa­ge. “Our goal is to offer an all-inclu­si­ve ser­vice,” said Acker­mann. “Our main mar­ket is fish far­mers who alre­a­dy have freshwa­ter pro­duc­tion and land far­mers who do not earn enough money with cows, eggs, etc.”

German market first

She said the com­pa­ny had tal­ked to some Ger­man restau­rants about gro­wing their own fish, but they were more inte­res­ted in buy­ing the fish from a far­mer. “But we have only tal­ked to smal­ler restau­rants. We have not yet tal­ked to lar­ger chains or sushi chains.” “We plan to sell the first Cubes next year and we are tal­king with pro­s­pec­ti­ve buy­ers in Ger­ma­ny. We plan to sell five or six next year,” added Acker­mann, who said the Cube had attrac­ted a lot of inte­rest from abroad, inclu­ding Isra­el and Sau­di Ara­bia. “The­re is a huge inte­rest in the con­cept but in the first year we will con­cen­tra­te on Germany.”


​100 litres of sludge

Acker­mann said the Cube pro­du­ced 100 lit­res of sludge per day. This had rela­tively litt­le salt in it, so land far­mers could mix it with their ani­mal manu­re, or it could be dis­po­sed of in the same way as other sewa­ge. “In the future we hope to use aqua­po­nics to get rid of sludge,” she explai­ned. Water repla­ce­ment for the RAS is 500 lit­res per day.

55 fish per day

The capa­ci­ty of the Cube is deli­bera­te­ly low – it works out at a con­ti­nuous year-round sup­p­ly of around 55 fish per day once har­ve­s­t­ing beg­ins – and is based on the mar­ke­ting rea­li­ty that SEAWATER Cube’s foun­ders expe­ri­en­ced at their university’s fish farm. “The farm could pro­du­ce up to 600 ton­nes per year, but they couldn’t grow sales fast enough,” said Acker­mann. “They were only able to sell 100 ton­nes of fish. “The Cube is made for the direct sales of fish, eit­her to the end con­su­mer or to restau­rants. It is only 50 or so fish per day, so you have time to build up your sales.”

SEAWATER Cubes will offer mar­ke­ting and sales sup­port, hel­ping new far­mers find sales oppor­tu­ni­ties tail­o­red to their indi­vi­du­al needs.

About the SEAWATER Cube

You can find all infor­ma­ti­on about the cube tech­no­lo­gy here.