Care
In the wild, Yellow Boxfish inhabit lagoons and semi-sheltered seaward reefs, with juvenile fish living cryptically amongst Acropora corals. These solitary fish are considered relatively poor swimmers and for this reason, developed protection via toxin release. Unfortunately, keeping YellowBoxfish in the home aquarium is very risky. This is a species notorious for readily excreting the poison ostracitoxin when stressed - a deadly toxin that is capable of wiping out an entire tank. Never keep more than one in the same tank as bickering and subsequent ostracitoxin release is very likely to occur. If tankmates are desired, they must be peaceful so as not to harass the boxfish; however, their continued safety will be precarious, hence why an aspecies-only set up is highly recommended. These fish have impressive teeth which are used to scrape algae (containing various microorganisms) tunicates and sponges off of rocks, and this forms the bulk of the diet along with various bivalves, snails, polychaete worms, mollusks, foraminiferans, and small fishes. For this reason, Yellow Boxfish are not suited to reef tanks, although there should be some live rock in the tank to provide welcome shelters and grazing opportunities. The tank must be very spacious and a large open swimming area should be provided so that the boxfish is able to swim out and about during daylight hours when usually they are at their most active. Despite their less-than-nimble method of locomotion, Yellow Boxfish is capable of jumping from open-topped tanks, so tight-fitting coverslides are a must. Care must be taken when carrying out maintenance on the aquarium, so as to keep the fish as calm as possible. Ideally, the tank will be situated where there is as little traffic going past as possible. Lights should turn on and off very gradually via the use of a dimmer - sudden bright light can shock the boxfish into toxin release. All foods should be offered towards the bottom of the tank to avoid the boxfish drawing in air when trying to take food from the surface. Boxfish have very small mouths and stomachs and it is of extreme importance that they are fed small amounts throughout the day to prevent starvation(something which may not always be immediately apparent because of the rigid bony plates along the sides of the boxfish). On account of this feeding regime, highly efficient filtration and protein skimming is a must. Juveniles (as pictured above) are bright yellow with black spots; but as the fish grows, the spots disappear and the fish takes on a blue-grey appearance with patches of subdued yellow. Although many an aquarist has been charmed by colourful young boxfish with their engaging, curious personalities, and somewhat cute method of locomotion, these fish are not suitable for beginners.
Feeding
An omnivorous species that should be offered small meaty frozen foods such as Mysis shrimp, Spirulinaenriched brineshrimp, chopped prawns/krill/mussel/cockle/clam/squid etc as well as herbivore foods including marine algae. Floating foods are not recommended as the fish may ingest air. Feed small amounts several times per day.
Breeding
Unlikely to breed in the home aquarium. It is thought that a male forms a harem with 2-4 females and the eggs are scattered in open water. The pelagic larvae are said to spend some time in the subtropical zone before migrating back to tropical waters.
