Like their pufferfish relatives, Boxfish are intelligent, curious fish that sometimes make their way into the fish trade. In many ways, though, they are not as desirable for home keeping as their cousins are, with some special considerations needed if you want long term success with them. Keep an eye on them, though, as a sick or dying Boxfish could cost you your tank.
Species
Ostraciidae is one of the 10 Families under the Order Tetraodontiformes along with the related Burrfishes (Diodontidae), Filefishes (Monacanthidae), Triggerfishes (Balistidae), and Pufferfishes (Tetraodontidae).
About 24 species of fish over 8 genera have been identified for the Family Ostraciidae. Of these, 7 are found in North American waters:
- Acanthostracion polygonius (Honeycomb Cowfish)
- Acanthostracion quadricornis (Scrawled Cowfish)
- Lactophrys bicaudalis (Spotted Trunkfish)
- Lactophrys trigonus (Buffalo Trunkfish)
- Lactoria diaphana (Roundbelly Cowfish)
- Ostracion meleagris (Whitespotted Boxfish) [pictured]
- Rhinesomus triqueter (Smooth Trunkfish)
Most of our Native Boxfish are on the duller side of the color spectrum, with lots of browns, dull yellows and grays and subsequently aren’t traded often. The exception is the Whitespotted Boxfish which is one of the more commonly sold members of this Family.
Conservation Status
To date, none of the Native Boxfishes have been evaluated by the IUCN for risk of extinction.
Distribution
The Whitespotted Boxfish is found on the Western Coast of Mexico, from the Gulf of California and down. This range overlaps with that of the Roundbelly Cowfish, though it is also found along the Southern-most part of California. The remaining species are found on the Eastern Coast, from Florida, South along the Gulf of Mexico, and into the Caribbean.
Description
Most of the Boxfish grow to be fairly sizeable fish in the range of 18-21 inches, when cared for properly (not that this size is often attained in the home aquarium). The Roundbelly Cowfish is smaller at around 13 inches maximum, and the Whitespotted Boxfish smaller still at 10 inches.
Boxfish are similar to Pufferfish, temperament-wise. They can be notorious fin nippers, though are not as aggressive as some of the more “psychotic” Tetraodontiformes like Queen Triggers. That said, Boxfish are individualistic and even among the different
species, often some fish are relatively peaceful and others are absolute
terrors. Housing with other fish species can be done with some, but
having a “Plan B” is always a good idea.
A dying or deceased Boxfish has a chance for releasing its stored Ostracitoxin into the water and, depending on the volume of the tank and sensitivity of tankmates, may kill some/most/all of its tankmates. A healthy, well-cared for Boxfish is unlikely to do this, though anecdotal evidence suggests that any stress can result in exuding toxins. Boxfish do not readily adapt to captivity so stress is always a concern when adding these fish to a system.
How can one prevent this sort of disaster? The four best methods are; good health (making sure your fish is in a big tank and is fed well), using Quarantine tanks (for both new arrivals and sick fish), not adding ANY of the shipping/transportation water to the tank, and (perhaps the best route), not including Boxfish in your community tank.
If you have a dead/dying Boxfish which is affecting your other livestock, you’ll first want to remove the offending fish and then perform a series of water changes. 30% changes a day or every other day for a week is a good practice, though in extreme situations you may want to change 50% or more on the first day.
Feeding
Feeding is one of the more difficult aspects to keeping Boxfish. Feed them items like high quality pellets (Spectrum is a good choice), green foods like Sushi Nori and marine Macro Algae, and meaty foods like Krill, Mysis, and pieces of chopped shellfish. It’s very important to include all three items regularly, as most Boxfish are lost due to malnutrition. Only add Boxfish to established systems with live rock and algae growth for them to graze on.
And make sure that food is added to the appropriate level of the tank. The Whitespotted Boxfish, for example, dwells at the bottom of the tank and should be fed there (spot feeding through a turkey baster, for example). Boxfish are not strong enough feeders to compete with eager surface feeders.
Like other Tetraodontiformes, they are not above eating smaller tankmates. Small fish have a decent chance to escape, but smaller invertebrates (shrimps, clams, crabs) will be eaten or killed in time.
Water Quality
As marine fish, especially those which are found in reef settings, Boxfish are best kept in large, stable systems. High carbonate hardness, high pH (around 8-8.5), and low levels of fish waste in the water are musts. They are best kept around a Specific Gravity of 1.021-1.025. Boxfish can potentially be large fish and produce a lot of waste. Utilizing Deep Sand Beds to aid in nitrification and a working protein skimmer are HIGHLY recommended with these fish. Live Rock will be chewed on by Boxfish but it may be key to success with keeping these fish.
The majority of Native Boxfish species are subtropical and should be kept somewhere around 66-70 F, with the Honeycomb Cowfish and Whitespotted Boxfish being tropical (and thus should be kept in the mid 70′s F). Heaters should be protected, preferably with PVC piping or kept in refugiums/sumps, as many Tetraodontiformes are known for biting through cords.
Brackish Suitability
None of the Native Boxfishes have been noted as being Brackish-tolerant.
Tank Size
For an adult Boxfish, the majority of species should be kept in a tank between 200-300 gallons, even for those nowhere near maximum size. The Whitespotted Boxfish shouldn’t be kept in a tank anything less than 150 gallons. Why such big tanks? Among other benefits, you’ll want PLENTY of volume to give you time to deal with potential Ostracitoxin exposure. In fact, you may want to use a sump to increase the volume further.
Breeding
Boxfish have not been bred in captivity.Final Thoughts
Boxfish have a small niche in the fish keeping trade, and the appeal is pretty apparent. They can be very pretty fish and are on the milder side compared to many of their relatives. Most species just don’t adapt to captivity well and can cost you all of your other fish. Is that necessarily common that a Boxfish will nuke a tank? Not really. But it’s not a risk I’d want to take. My advice? Just leave Boxfishes in the oceans where they come from or enjoy them at your local Public Aquarium.
Sources
Fish Identification, Fishbase (US)
Fish Identification, Fishbase (Mexico)
The Puffers Called Box-, Cowfishes, family Ostraciidae, Bob Fenner
FAQs about Box-, Cowfishes Systems, Wetwebmedia
FAQs about Box-, Cowfishes Compatibility, Wetwebmedia
