That Fish Blog – Aquarium Advice and Information

Hello, Frank Indiviglio here.  Angelfishes (Family Pomacanthidae) represent to many the “classic marine aquarium fish” – vibrantly colored, active, alert and somewhat delicate.  Ranging in size from 4 to 24 inches, an angelfish of one kind or another is responsible for luring a great many people into setting up their first marine aquarium.

Diversity and Range

The 74 described angelfishes range throughout the tropical Atlantic, Pacific and Indian Oceans, and generally occur in shallow water (less than 60 feet in depth), often in association with coral reefs.  All are somewhat compressed in profile and spectacularly colored.  A great many species exhibit long, trailing extensions from the dorsal and anal fins.

Adult-Juvenile Differences

Juvenile and adult angelfishes of the same species often exhibit striking differences in coloration…so much so that the young of several were initially given full species status.  A number of theories have been proposed to explain this phenomenon.  Young angelfishes of some species consume external parasites from the scales of larger fish.  It may be that their unique coloration advertises this role to larger fish, which might otherwise make a meal of them.  Such coloration may also inhibit aggression from the normally territorial adults of their own species

Angels in the Aquarium

Although the cherubfish (Centropyge argi) and certain other dwarf angels are fairly hardy, angelfishes are not recommended for inexperienced hobbyists.  Most are intolerant of sub-optimal water conditions, and a number are fairly specific in their food requirements, subsisting largely upon sponges, corals and fish eggs, and therefore difficult to acclimate to captive diets.

Diet

Angelfishes with less specialized dietary requirements should be offered a wide variety of live, freeze dried and frozen foods, including brine shrimp, mysis, squid, prawn, algae and mollusks.

Be aware that large angelfishes may not bother to eat live brine shrimp and other tiny creatures.  In fact, such may be pulled into the fishes’ gills during respiration, causing irritation and stress.

Environment

Despite being quite active swimmers, all angelfishes require rocks and coral among which to shelter for the night.  Dwarf species in particular require a great deal of structure in the aquarium, as much of that time is spent in and around such in the wild.  Deprived of secure hiding spots, most will languish and die.

Reproduction

Among this family we find species that are hermaphrodites and others that utilize virtually every reproductive strategy known to fishes – monogamy, promiscuity, harems and leks (in which groups of males gather to display before females).  Although captive breeding is not routine, several species of angelfishes have successfully reproduced in private and public aquariums.

Outwardly very similar, the sexes may sometimes be differentiated by the swollen abdomen of the gravid female.  In those species that exhibit monogamy, mated pairs rise upward together, releasing eggs and sperm as they go.  The tiny eggs float about among the plankton, and, after a time (which varies from species to species but averages1 month in length), the minuscule fry settle to the ocean’s floor.

I’ll cover individual angelfish species in the future.  Until then, please write in with your questions and comments.  Thanks, Frank Indiviglio.

Further Reading

For detailed information on some of the largest and smallest of the angelfishes, please see the following excellent articles, also posted on this blog: Species Profile: Pygmy Angels http://blogs.thatpetplace.com/thatfishblog/2008/05/02/species-profile-pygmy-angels/ and Species Profile: Queen Angel http://blogs.thatpetplace.com/thatfishblog/2007/09/12/species-profile-queen-angel/.

Hello, Frank Indiviglio here. Stingrays – mysterious, beautiful and odd – are difficult to resist, and therein lies their main drawback as aquarium fishes. While not particularly delicate, experience with other fishes does not always serve one well where stingrays are concerned. Their husbandry is not well known, and there are a number of special considerations which must be borne in mind.A marine species (the little skate, Leucoraja erinacea) was the first ray to catch my attention. I was about 7 years old, prowling the stalls of NYC’s famous Fulton Fish Market in the pre-dawn light. Accompanied by my grandfather, we were seeking new pets – octopus, turtles, eels and such – that rarely appeared in pet stores at the time. The skates, while living, were in bad shape, but I vowed to give them a try someday. Eventually, freshwater rays appeared in Manhattan aquarium shops, and I was off and running.

Following are some points to consider before purchasing your first freshwater stingray. Having a handle on these matters beforehand will greatly increase your chances of succeeding with these spectacular fishes.

Medical Precautions
Stingrays are venomous animals. While no freshwater species are known to have caused human fatalities, we know very little about the nature of the toxins they produce, and individual sensitivities may be a concern.

Speak with your doctor and arrange for medical care in the event of an emergency before purchasing a stingray.

Selecting an Individual: Size
The small stingrays that appear in the pet trade are not adults but rather are babies of a variety of large species. Even those sold as “teacup rays” will reach at least 18 inches in diameter when mature (2-3 years), and will require a tank measuring 4′ x 2′ x 2′ if they are to thrive. Adults of several trade species approach 3 feet in diameter.

Furnishing the Aquarium
Stingray skin is easily damaged by ornaments that are safe for other fishes; they do best in a sparsely-furnished aquarium. Even small specimens will quickly uproot plants and dislodge filter tubes, aerators and heaters.

Use smooth stones as a substrate. Typical aquarium gravel is too rough and may cause skin lesions. Substrates designed for marine aquariums raise the pH to dangerously high levels and sand, while acceptable, poses water quality problems (please write in for further details).

Stingrays often alight upon aquarium heaters, but seem not to respond to the high temperatures generated. Heaters must always be shielded by a PVC sheath or heavy rocks.

Personal Observations in the Field
While on a field research assignment in Venezuela, I was happily situated within the range of 4 species of freshwater stingrays. The animals spread out onto the flooded grasslands during the rainy season, and were rather easy to find.

The largest individual I observed was dead and floating down the Orinoco River. Spanning nearly 4 feet across, it easily supported the weight of the black vulture that was feeding upon its carcass.

A Hands-On Experience with Stingrays
Please be sure to visit That Fish Place/That Pet Place in Lancaster, PA (the world’s largest pet store) for a chance to hand feed our friendly marine stingrays.

More to follow next week. Until then, please write in with your questions and comments. Thanks, Frank Indiviglio.

Further Reading
Please check out the book Freshwater Stingrays.

An interesting article on the conservation of South American stingrays is posted at http://www.cites.org/common/com/ac/20/E20-inf-08.pdf.

Image referenced from Wikipedia and originally published by Raimond Spekking.

Hello, Frank Indiviglio here.  Involvement in exciting and important conservation work need not be limited to those select few fortunate enough to have turned their hobbies into careers.  Especially in today’s economy, many vital research and recovery efforts rely heavily upon the work of volunteers.  Getting out in the field (or pond, river and swamp, as the case may be!) is a wonderful way of expanding your fish-keeping horizons.  Today I’d like to focus on fresh water species; I’ll cover marine fishes in the future.

Conserving Desert-Dwelling and other Rare Fishes

The North American Native Fish Association http://www.nanfa.org/ sponsors a number of conservation initiatives, all of which utilize volunteers.  Particularly active in the conservation of desert spring fishes and others in similarly precarious habitats, current initiatives include assisting the US F&W Service in removing introduced plants, fishes, crayfish and bullfrogs from critical Moapa spring fish habitat, training university and government researchers in fish sampling techniques and participating in reintroduction efforts. 

NANFA members also get to indulge their fish-keeping interests, establishing native fish aquariums in schools and nature centers and advising caretakers on husbandry and breeding techniques.

A Wide Range of Field and Captive Care Opportunities

The Native Fish Conservancy maintains an extensive collection of articles on native fishes and fish conservation.  If you are unsure of where to start, a review of these would be invaluable in jump-starting the process and providing numerous options. 

Through their “Adopt-A-Tank” program, NFC members also help schools set up and maintain native fish aquariums and assist students in sampling local fish populations…the best of both worlds!

Native Fresh Water Fishes in the Aquarium

Some of our smaller sunfishes have long been popular with aquarists in Europe, but in the USA native fish-keeping is a lost (or barely developed!) art.  I do not quite understand why, as many are interesting, brilliantly colored and little-studied.  Species diversity here is quite high…even over-crowded New York State boasts nearly 150 freshwater fishes, many of which do quite well in captivity (interesting note: more species of fish have been identified in the Amazon River than in the entire Atlantic Ocean!).

North America is populated by a wide variety of gorgeous sunfishes of all sizes (our massive large-mouth bass is, technically, a sunfish).  With colors rivaling those of any tropical species and providing extensive care to their eggs and young, these are, along with yellow perch (please see photo), long-time aquarium favorites of mine.  Another neglected species, the American eel, lived in my collection for 17 years, and a pair of brown bullheads that I bred in an outdoor pond provided a notebook-full of observations that I treasure to this day (males are unbelievably protective of their tadpole-like fry, herding them about for quite some time).

I’ll cover the care of various native fresh water fishes in future articles.  Until then, please write in with your observations, experiences and questions.  Thanks, Frank Indiviglio.

Further Reading

The US Fish & Wildlife Service currently lists nearly 150 species of native freshwater fishes as threatened or endangered.  Information on each, along with links to recovery plans (some of which encourage volunteer participation), is posted at www.fws.gov/endangered/wildlife.html#Species.

The Cold Spring Harbor Fish Hatchery  http://www.cshfha.org/ houses an extensive collection of fresh water fishes, amphibians and reptiles, and is well-worth a visit by native fish enthusiasts.

Three fishes, including the minute Satomi’s pygmy seahorse (Hippocampus satomiae), were among the newly-described species voted to the “Top Ten” list, which is published annually by the International Institute for Species Exploration at Arizona State University.  Another nominee, Materpiscis attenboroughi, an extinct fish fossilized in the act of giving birth 380 million years ago, provided the oldest record of live birth among vertebrates (please see photo).  The deep blue Chromis (Chromis abyssus), a gorgeous blue damselfish that thrives, in contrast to other family members, at depths of over 350 feet, is the third fish listed.

Tiny and Well-Camouflaged Seahorses (Seaponies?)

Measuring just 0.45 inches in height, Satomi’s pygmy seahorse (first collected, fittingly enough, by diver Satomi Onishi), lives off Derawan Island, Indonesia and northern Borneo, Malaysia.

Prior to its discovery, the title of smallest seahorse went to Bargibant’s seahorse (Hippocampus bargibanti) which, at 0.8 inches, now seems a giant!  Bargibant’s seahorse bears an uncanny resemblance to the polyps of the gorgonian, or soft coral, upon which it lives (please see photo).  In fact, the first specimens described (1970) had lived in a small aquarium, attached to a gorgonian, for several days before being discovered by a startled researcher.

Further Reading

“Standing” an impressive 0.9 inches in height, Florida’s dwarf seahorse is our smallest native species.  Both it and the much larger Atlantic seahorse make fairly good choices for folks interested in keeping members of this fascinating but delicate family of fishes.  Please see my article The Natural History and Care of Native Seahorses for more information.

If you are interested keeping many varieties of seahorses in the aquarium and discovering how they live in the wild, please check out my book Seahorses, A Complete Pet Owner’s Manual.

Please write in with your questions and comments.  Thanks, until next time, Frank Indiviglio.

Hippocampus bargibanti image referenced from Wikipedia and originally posted by Jnpet

Materpiscis attenboroughi image referenced from Wikipedia and originally posted by Sularko

Hello, Frank Indiviglio here.  In the jawfishes (Family Opistognathidae) we find some of the most entertaining and interesting of all marine aquarium subjects.  Constantly popping in and out of their uniquely constructed burrows, all are very active and quite comical to behold.  Although perpetually occupied with minor territorial disputes, they get along well in groups, and are quite willing to display a wide range of interesting behaviors once they settle in.

Diversity and Lifestyle

Over 60 species of jawfishes, all inhabiting marine waters, may be found in the Indian Ocean, Western and Central Atlantic Ocean and the Pacific Ocean (from the Gulf of California to Panama).  

Jawfishes sport huge eyes and mouths on an enlarged, blunt head that, to many, evokes the image of a bulldog.  The body tapers quickly behind this, suiting them well to the burrowing lifestyle that all have adopted.  The strong jaws and head are used to hollow out subterranean retreats, while the slender body allows the fish to quickly slip inside, tail-first, at the slightest sign of danger. 

Jawfishes rarely stray far from home, making short feeding or defensive forays but generally staying within easy reach of the burrow’s entrance.  Most cover the entrance of their homes with a pebble at night, and the males of all species incubate the eggs within their mouths.

Yellow-Headed Jawfish (Opistognathus aurifrons)

A group of these beautiful fishes in established burrows makes a delightful exhibit, with bright yellow heads constantly appearing and disappearing as they survey their territories for food or foes.  They slip tail-first into their homes with amazing speed, and pop out just as quickly.  Growing to a length of 5 inches, the body of the yellow-headed jawfish is delicately colored in pale blue. 

In contrast to many other fishes that maintain a regular home base, yellow-headed (and most other) jawfishes are relatively inoffensive towards one another.

Providing the Right Substrate

Jawfishes require a substrate that allows for the creation of burrows that retain their structure and can serve as permanent homes.  Without such, they will fare poorly.  You may need to do a bit of experimenting, in terms of substrate composition, if you add jawfishes to an established aquarium. 

If you are starting from scratch, a 1:1 mix of our Natural Ocean Substrate  and Pearl Beach Aragonite will work well.

Diet

Jawfishes readily feed on all manner of animal based frozen and pelleted  foods, and particularly relish live brine shrimp, Mysids and blackworms.

They are quite alert and vigorous feeders, but please be aware that many individuals will not venture far from their burrow.  Therefore, be sure that a suitable amount of food is placed within easy reach, lest they be out-competed by less “homebound” species.

A Caution

Jawfishes scuttle about but rarely swim, and so we tend to think of them as “bottom fish”.  However, for reasons as yet unexplained, they frequently manage to jump out of aquariums at night. 

I’ve not had the opportunity to watch jawfishes with the assistance of a night-viewing bulb, so as to perhaps understand just what it is they do after dark…please write in if you beat me to it.  In the meantime, be sure that your aquarium hood fits securely, especially around filter tubes and other equipment.

Further Reading

The Monterey Bay Aquarium exhibits yellow headed jawfishes, and has posted interesting information here.

Please write in with your questions and comments.  Thanks, until next time, Frank Indiviglio.