Rare in the aquarium trade because it lives in the open ocean. This fish is for public-aquarium-sized systems: it outgrows home aquaria and needs a very large volume of open swimming space, so no home tank size is given. Water figures given here are general marine aquarium guidance, not species-specific: 24–27 °C, pH 8.1–8.4 and salinity SG 1.020–1.025 (fish-only systems). It travels with sharks (especially the oceanic whitetip), rays and sea turtles, eating parasites and leftover food; young fish shelter under jellyfish and drifting seaweed. It often follows ships. When excited its dark bars fade and the body turns silvery with blue patches. The article gives 60–70 cm as the maximum. Selling: our policies require the adult size and long-term tank needs to be stated clearly in the listing. Large fish must travel by a specialist live-animal courier (see the Livestock shipping guide). Sources: Wikipedia, List of marine aquarium fish species (en.wikipedia.org/wiki/Listofmarineaquariumfishspecies); Wikipedia (en.wikipedia.org/wiki/Naucratesductor). Checked October 2026.
Diet
A carnivore that picks parasites and scraps from its host animals. In captivity offer chopped fish, squid, krill and prawn.
Breeding
Not covered in our sources; not bred in captivity.
Compatibility and tank mates
Best kept with the large sharks, rays or turtles it naturally follows in a public aquarium. Not suitable for reef tanks.
Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.
About Aquatic-Auctions
Aquatic-Auctions (aquatic-auctions.com) is a UK online marketplace for aquarium and pond livestock and equipment: tropical and marine fish, corals, shrimp, snails and other invertebrates, aquatic plants, tanks, filtration, lighting and food.
Items are sold by auction, buy it now or classified advert, by hobbyist and business sellers in the UK.
Buyers pay sellers directly; Aquatic-Auctions does not hold the money. Hobbyist sellers must offer PayPal and may also take cash on collection. Business sellers take PayPal (required) or cash on collection, and bank transfer only once they have a seller rating of 50 out of 100, a company and pet-selling licence checked by Aquatic-Auctions, a bank account in the company's name, and bank details approved by Aquatic-Auctions.
Buyers are told to pay by PayPal Goods & Services, never PayPal Friends and Family, gift cards or crypto.
Live fish and other vertebrates must be sent by specialist live-animal couriers (for example APC Overnight or DX Express), never by Royal Mail. Some invertebrates and plants may go by Royal Mail Special Delivery or 1st Class within its rules.
Banned and invasive species (for example those on the GB invasive species lists) cannot be listed, and sellers must meet the site’s animal welfare standards.
Members must be 16 or over to buy (16 and 17-year-olds with a parent or guardian’s agreement); sellers must be 18 or over.
Business sellers show their address, company details and pet-selling licence to buyers. Seller ratings run from 0 to 100: +1 for each positive feedback, −1 for each negative.
The site includes a free community species wiki with care guides (water parameters, tank size, diet, temperament, breeding).
Aquatic-Auctions is run by Etavonni Tech Limited trading as Aquatic-Auctions (company number 10204188), Aldershot, Hampshire, UK. Contact: info@aquatic-auctions.com.