Archive for June, 2009
Marine Angelfishes: an Overview of Natural History and Captive Care
Jun 29th
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/.
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Loading ...Rocky is Spared: The Plight of One Family to Save their Beloved Pet
Jun 26th
There aren’t often stories in the news about fish that give you warm fuzzies, but this one came pretty close. Fish people are passionate about their pets, and though you typically can’t cuddle them or play fetch with them, to many of us they are just as loved as the family dog or cat. Rocky’s story is an example of the love one owner feels. Rocky may not be the fish that many of us picture as a fun pet, being that he is a snakehead, and we know the trouble they cause, but I have to say that this particular fish I feel for. His responsible keeper deserves a pat on the back for fighting for his pet’s life and for being said responsible keeper. I guess we can’t let all fish fall victim to invasive species profiling.
Here are just a couple of links to articles on Rocky’s plight, there are tons more if you search:
http://www.syracuse.com/news/index.ssf?/base/news-17/1235642273151050.xml&coll=1
http://www.nydailynews.com/news/2009/03/17/2009-03-17_suburban_syracuse_family_begs_gov_paters.html
(No Ratings Yet) Loading ...Overgrowing Pond Plants and Invasive Species
Jun 24th
It’s starting to get warm. Really warm in the U.S. And, for many of you, you’re starting to notice your pond plants are starting to kick it into overdrive.
Pond Plants, more than most other plants in my opinion (probably because they always have access to water) can really kick into growth once the water temperature goes up. I’ve been one of the folks who literally starts throwing away the water hyacinths I paid 4 bucks for a few months earlier because I have no where to go with them. I’ve seen the dwarf moneywort in my pond run out of room within and establish itself OUTSIDE the pond. Even hardy pond lillies, while beautiful, can go to town in a mud bottomed pond.
It is these rapidly growing plants which form some of the most environmentally invasive species available. Imagine, what’s happening in your pond allowed to carry on unabated in a large lake? Unless you can properly dispose or trade them, do not introduce them back into the wild. The threat of serious ecological impact is particularly strong from these seemingly unstoppable plants.
Many local garden clubs or websites will be happy to share and swap out plants with you. You may even be able to pick up a new species or 2 for your water garden. As in all things, consider the impact before you act…..
For more information on invasive plant species within the US, check out invasivespeciesinfo.gov.
(No Ratings Yet) Loading ...Freshwater Stingrays: Points to Consider Before Your First Purchase
Jun 22nd
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.
(No Ratings Yet) Loading ...Fish Geek TV – River Monsters
Jun 19th
So there are those of us out there that find ourselves channel surfing on a Sunday night in a desperate attempt to find something worthwhile to watch. I usually turn to the educational /animal/nature side of things, History, Discovery, you know, not just mindless drivel that pollutes the airwaves. A few weeks ago, I came across a fun series on Animal Planet, and as a “fish geek” I became captivated.
The show is called River Monsters, and if you haven’t seen it you may want to check it out. It may not be up the level of Blue Planet or Planet Earth, but it does capture some amazing footage of the host catching and releasing some of the more monsterous (if not in behavior, certainly in size) fish in the world’s rivers and lakes. These are the kind of fish that inspire Sci-fi writers!
Being in the business, I am familiar with most of the species the host, angler Jeremy Wade seeks out, but it is pretty amazing to me to see adult specimens alive and in their native habitat from the comfort of my sofa. Some of these fish are even common imports, and the show is great proof that most home aquariums are not and will never be large enough to accommodate such species comfortably, a whole new meaning to “this fish gets big.” If you’re looking for some entertainment on Sunday night, check it out, or take a look at the site:
http://animal.discovery.com/tv/river-monsters/
And check out “Natures Most Amazing Events” on Discovery if you like the Blue Planet and Planet Earth series.
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