The Butterflyfishes, Family Chaetodontidae, for the Home Aquarium
Butterflyfishes are some of the mainstays in the Marine trade and interestingly enough, many of them are Native to the continental US (many more are native to Hawaii, though). Widely sold and pleasantly to behold, the Butterflyfishes have a lot to recommend them. It’s not all a walk in the park, however, and there are some things to know before getting these for your Marine community tank.
Species
Butterflyfishes are the Family Chaetodontidae, under the Order Perciformes (the largest Order of Vertebrates) and the Suborder Percoidea (along with Seabasses, Scats, Snappers, Moorish Idols, and many more). The Family is comprised of about 120 species over 10 Genera, and 7 of these species are native to the continental US:
- Chaetodon capistratus (Foureye butterflyfish) [pictured]
- Chaetodon ocellatus (Spotfin butterflyfish)
- Chaetodon sedentarius (Reef butterflyfish)
- Chaetodon striatus (Banded butterflyfish)
- Prognathodes aculeatus (Longsnout butterflyfish)
- Prognathodes aya (Bank butterflyfish)
- Prognathodes falcifer (Scythemarked butterflyfish)
Interestingly, each one of these can be found in the Marine trade if you look long and hard enough. Most are more or less common though the Bank and Scythemarked Butterflyfishes are more rare. Still, if a certain species is desired, it can be purchased if you put in enough effort.
Conservation Status
Though this Family does experience mild to moderate pressure in terms of collection for the Marine fish trade, each of these Butterflyfish populations are currently considered stable and designated Least Concern by the IUCN.
Distribution
Six of the seven species of Butterflyfish are all confined to the South Eastern coast of the United States, into the Caribbean, and along the Southern Coast of Mexico. Oddly enough, they are much less abundant in the Gulf of Mexico than in the surrounding waters. The Bank Butterflyfish is found in more Northern Waters as well, as far up as Virginia.
The Scythemarked Butterflyfish is the only one found on the West Coast, from Southern California into the Gulf of California.
Description
These Butterflyfishes are generally small fish. The smallest, the Foureye and Longsnout Butterflyfishes, typically reach 3 to 4 inches, and the Spotfin Butterflyfish reaches about 8 inches. The other species have a maximum length of around 6 inches.
Butterflyfishes are non-territorial and non-aggressive with other fish, though may be pushier with other members of the same species. In a larger tank with lots of cover, they will likely cohabitate without many problems. The majority of these species (the Foureye, Spotfin, Banded, and Longsnout Butterflyfishes) can be very timid within the confines of an aquarium and are easily picked on by all but the most peaceful of tankmates. These species are somewhat prone to “mysterious deaths” due to stress from capture, transport, housing, tankmates, feeding (or lack thereof) and are probably best avoided for home use.
Butterflyfishes have been known to jump out of tanks when they feel like it, so tanks with lots of cover (as well as a sturdy cover!) will help keep them in the tank and feeling secure.
These fish do seem to be prone to diseases, from Crypt and Velvet to Gill Flukes. They are very sensitive to such conditions and are among the first fish in the tank to show illnesses during an outbreak. Luckily, they do not appear to be overly sensitive to common medications like Copper or Malachite Green. Always consider quarantining for a few weeks to determine if the fish is healthy or sick upon arrival.
Feeding
Feeding depends on the specific species, and can vary from generalized omnivore to very specialized. The majority of these Native fish are easy to feed, and (if they accept foods, there is no guarantee) at first can be fed with smaller live foods like blackworms and brine shrimp. After acclimating, they should be able to be fed on frozen foods like Mysis or chopped shellfish. Consider using vitamin supplements like Selcon with these fish.
The Spotfin and Bank Butterfly fishes are specialized feeders and tend to feed only on Coral Polyps. Even if they eat, it can be difficult feeding them for an extended period of time and even with outbreaks of pest anemones like Aiptasia, they may consume all until there is none left to sustain themselves.
Butterflyfishes of all types will likely pick at invertebrates in the tank, sampling shrimps, corals, anemones, clams, and the like. For the non-obligate coral eaters, a fish-only system is the best choice.
Water Quality
These fish absolutely require clean and consistent water if they are to have a shot at long term survival. With a narrow pH requirement (pH 8.2-8.3), consistently high salinity (1.025-1.026), one can infer that they simply do not adjust to changes very well. The Foureye, Bank, Reef, and Scythemarked Butterflyfishes are Subtropical and can be kept at room temperature (64-68 F, no higher than 70 F) while the remaining species are Tropical and 75-80 F is a better temperature for keeping.
These fish need very low concentrations of wastes to do well. Nitrates should be kept under 10 mg/l at all times, and these fish absolutely require a skimmer and live rock in their systems. Do not keep these fish in newly established systems, and only introduced to your tank once it has been up and running for a number of months or a year.
Brackish Suitability
Though some species of Butterflyfishes are sometimes found in brackish waters, none of these species are brackish tolerant. Some aquarists like keeping their fish-only marine systems in a state of hypo-salinity (at a lower than Near Sea Water (NSW) salinity) for lower costs… I would not recommend it with the Native Butterflyfishes.
Tank Size
The smallest species, the Foureye and Longsnout Butterflyfishes, could be kept in a 55 gallon system specifically set up for these animals, but 75 gallons is likely a better starting point. Likewise, the remaining species could be kept in a 75 gallon tank, though really 125 or 150 is better. Remember, tank size is more than just “will it fit in this enclosure” and many Marine fish are harmed (psychologically; physically by inadequate waste dilution) by being kept in smaller systems.
Breeding
Butterflyfishes reproduction habits seem to depend on species. Some appear to form monogamous pairs, others spawn in groups, or form short lived associations. They do appear to be seasonal spawners, with tropical spawning activity peaks in winter and early spring, while species in more temperate areas spawn in midsummer. Time of day may also trigger breeding behavior, as it is often witnessed just before nightfall.
Due to the Butterflyfishes relative intolerance to conspecifics in all but the largest of tanks (upwards of 600 gallons) and the difficulty (sometimes, impossibility) of determining sex of the fish outside of mating, this makes reproduction in the home aquarium very difficult.
Final Thoughts
Looking for a relatively small, peaceful fish for your Native Marine tank? Look no further than the Butterflyfishes, which are gentle and attractive fish that typically have no problems playing nice with your other (non-boisterous) tankmates. Better yet, these fish are widely sold and easily available. That said, some are better pet fish than others, and some should be outright avoided.
Sources
Fish Identification, Fishbase
Butterflyfishes; Separating the Good Ones and Those You Don’t Want, Bob Fenner
FAQs on Prognathodes Butterflyfishes, Wetwebmedia
FAQs on Butterflyfishes Foods, Feeding, Nutrition, Wetwebmedia
FAQs on Butterflyfish Systems, Wetwebmedia
ADW: Chaetodontidae: Information, Animal Diversity Web
