Spotted Boxfish Care Guide

Scientific NameOstracion meleagris
Minimum Tank Size125 Gallons
Water Parameters72-78 F, pH 8-8.4, Salinity 1.020-1.025
The spotted Boxfish, also known as  White Spotted Boxfish or black box fish, is a rare fish with big risks associated with them. They have a lot of personality to them and are easy to care for once established in the aquarium. Unlike most boxfish they undergo dramatic color changes between the two genders and are much smaller. They are also more rare, making them a great show fish for expert aquarists. This being said they should be exclusively kept by Expert Aquarists Only.

Why are these boxfish so demanding? As a defence mechanism the Spotted Boxfish houses deadly neurotoxins in its body. When stressed or harassed it can release these toxins to scare off the other fish. In the large ocean these poisons are quick to spread and dilute in the water until it is ineffective, meaning fish hit by their poison will swim off and stop bothering the boxfish. In an enclosed environment like the aquarium these poisons do not disperse and instead stay concentrated. This will quickly kill any fish in the aquarium, sometimes even the boxfish itself. The poison is difficult to see and is mostly identifiable by a foamy surface on the aquarium. If the Spotted Boxfish releases its toxins the owner has a very short window in which they can remove fish from the tank and place them into a hospital tank before they die. Once in the hospital tank the water should be changed frequently and treated with carbon to help reduce the effects of the neurotoxins. Most people will not have a second large tank ready for all of their fish and will lose most if not all of their fish if the boxfish becomes upset.

Photo credits belong to NOAA photo library on flickr and Bernard Dupont for the top and bottom photos respectively.

These dangers only happen when the boxfish is especially stressed out or receives attacks from their tankmates. When the aquarium is tailored to accommodate the Spotted Boxfish they are unlikely to ‘bomb’ their tank with poisons.

The Spotted Boxfish is much smaller than the other boxfish, coming in at under 10 inches in length. In the aquarium they will not typically grow to their full size and should only reach 8 inches at the most. In especially large tanks where they feel comfortable and unrestricted they may reach their maximum length after years of ownership.

Is the Spotted Boxfish Reef Safe?

The Spotted Boxfish is not particularly reef safe but may be kept with some inverts, branching corals or various SPS corals. Corals with large, easy to bite polyps or fleshy bases should be avoided, as they will typically nip at or eat these entirely. Some boxfish will not eat any corals or harass even the smallest shrimp, but you should not count on getting the nicest boxfish. Instead pick only suitable corals and inverts.

Worms, scallops, mussels, clams and sponges will be in danger when kept with the Spotted Boxfish. They especially enjoy eating any exposed fleshy parts like worms and clams. Tube worms and feather dusters should also be avoided. The Spotted Boxfish uses jets of water from its mouth to blow around sand and find burrowed worms. While not as good as wrasse at hunting worms they should be considered an extreme threat.

Hard shelled inverts like crabs are fine with this box fish as are large shrimp. Anything under two inches may be targeted as food, however most shrimp are fast enough to escape the slow swimming box fish. Cleaner shrimp will try to clean the box fish but have difficulty holding onto their rough shell like bodies.

Despite eating many corals the Spotted Boxfish enjoys spending its time in coral reefs and will typically make branching coral its home. Try to have at least one large branching coral for them to rest around. Otherwise they will use overhangs or large caverns for their home.

Spotted Boxfish Diet

The Spotted Boxfish has a straight forward diet but can be difficult get eating in a new aquarium. Boxfish suffer from shipping stress more than most fish and are quick to hide and avoid any other fish that are drawn towards feeding time. It is typically a good idea to keep the Spotted Boxfish in a smaller hospital tank for awhile while feeding it high quality foods. This makes sure other fish do not keep them from their foods and allows you to watch the boxfishes behavior towards different kinds of food. If they are kept in a tank with live shrimp the should at least graze on these while you try to transition them to more stable food sources. You can also use ghost shrimp, but these are much quicker and should have their tails cut so that the boxfish can catch them.

They should always be offered high end foods once they are added to the display tank. Foods like like baby brine shrimp, mussels or chopped squid. They may accept flake foods but should be fed more filling foods. For prepared foods use pellets rather than flakes.

The Spotted Boxfish diet should contain:

  • Dried brine or mysis shrimp
  • Live gut loaded brine shrimp
  • Chopped table shrimp
  • Frozen foods
  • Chopped Squid
  • Clam
  • Mussels
  • Sponge based foods or sponge
  • Seaweed
  • Algae

The Spotted Boxfish should be fed in small amounts over a longer than normal feeding period as they have difficult catching any moving foods. Large quick feedings can have them miss the majority of the food while allowing their tankmates to eat food that was intended for the boxfish. With particularly competitive fish target feeding the Spotted Boxfish may be mandatory.

Feeding seaweed is a great way to get the Spotted Boxfish herbivore nutrients. The two things to remember when feeding seaweed are:

  • Remove any uneaten seaweed after 1 hour
  • store the seaweed in a dry area

Most seaweeds will be dried for long shelf life. When it gets re-hydrated it starts to break down. When placing dried seaweed in the tank it will typically stay solid just over an hour, breaking apart and polluting the water unnecessarily. If the seaweed goes uneaten for an hour it should be removed from the aquarium to prevent this form happening. Removed seaweed should be discarded as it will break down much quicker if added back to the tank at a later date.

Once opened the seaweed should be kept in a drier area. The room with the aquarium is usually fairly humid and can negatively affect the dried seaweed before it is ever added to the tank. As seaweed is frequently used in foods it can be safely kept in a pantry with normal food.

The two types of seaweed for the sold are red and green. These offer a different set of nutrients and should be alternated whenever possible. The red seaweed will usually break down quicker than green seaweed. Using only green seaweed is not a bad choice but the variety of nutrition two types of seaweed offer can help the Spotted Boxfish stay healthy.

Spotted Boxfish Tank Requirements

While not particularly demanding this boxfish should be kept in a tank made with them in mind. They should not be added to any existing aquarium that they may not be compatible with. The main things to avoid are tons of small caverns and high flow tanks made for fast swimming fish. Additionally to avoid harassment form other fish the boxfish should be added to the tank early if not be the first fish allowed in the aquarium.

The Spotted Boxfish should be kept in tanks with large spaces between rocks or large caverns that they can fit in and turn around without difficulty. Overhangs are also popular places for them to hang around. Large flat rocks at the top of the tank give them a good area to scrape off growing algae. Avoid using small caverns that the boxfish cannot fit in once it is fully grown. While their bodies are quite hard they can still be cut or scraped by live rocks if they try to swim between them.

Boxfish frequently live around large outcroppings of coral, both to feed and for their homes. They will usually nip at or eat large polyp corals, known as LPS corals. They can be kept around SPS, small polyp stony corals, and do well when kept with branching corals. They will frequently hang around these branching corals and even rest on them. Their presence can dissuade other fish from bothering the corals making this a somewhat mutually beneficial relationship.

Strong currents should be avoided as the Spotted Boxfish is not shaped to weave through the water. Their large flat sides are very easy to push around using powerheads or even strong water pumps/returns. Ensure there are a lot of low flow areas for the Spotted Boxfish to spend its time. If there are no slow moving areas the boxfish can easily become stressed and is much more likely to use its toxins to defend itself form fish that have claimed the slow moving areas. High flow tanks will frequently lead to dead boxfish.

Spotted Boxfish Tankmates

Spotted Boxfish do not interact with the other fish in the tank much. They may sometimes clean off large fish while they are small but tend to float around and just watch other fish as they pass by each other. They should not be kept with any other boxfish or similar looking puffer fish. Very large tanks may be able to pair multiple boxfish, however they will generally fight in any tank under 250 gallons, leading to the aquarium being bombed with their neurotoxins.

Do not keep the Spotted Boxfish with aggressive fish. Triggers, groupers and scorpionfish should be avoided entirely. Even smaller aggressive fish that can chase the Spotted Boxfish away should not be kept in the same tank. While their hard shell like body makes most of this harassment harmless continued attacks will encourage them to release poisons.

Good tankmates are:

  • Dwarf Angelfish
  • Clownfish
  • Cardinalfish
  • Chromis
  • Butterfly Fish
  • Peaceful Angelfish
  • Wrasse
  • Anthias

Hard shelled inverts and large shrimp will generally be safe with the Spotted Boxfish. Most shrimp will be far to quick to be caught by boxfish. While they may take several nips at the shrimp they are likely to give up on hunting them. Cleaner shrimp will try to clean the boxfish but have trouble staying on them due to their hard shell like body.

Snails are typicaly not a target as the Spotted Boxfish jets of water cannot dislodge them. They can flip over sand sifting snails but don’t seem to hunt them. Clams, oysters and sponges should not be kept with the Spotted Boxfish as they will be grazed on until they die.

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