Motherhood in Crayfish, A personal observation

Please welcome back Frank Indiviglio to That Fish Blog. Frank gives his unique perspective on another interesting, sometimes aquarium inhabitant, the crayfish.

Freshwater crayfish, found on all continents except Africa and Antarctica (the southeastern United States, home to 80% of the world’s species, is a hotspot of crayfish diversity), are often purchased as an “oddity” or scavenger to add to the aquarium. However, these active Crustaceans make fascinating pets in their own right and are well worth more attention. I will write more about the specifics of crayfish care in future articles, but would now like to recount my experience with the maternal instincts of one species, the red swamp crayfish, Procambarus clarkii.

It is difficult to house crayfish in groups, as they tend to consume tank-mates that have recently molted (newly-molted crayfish are soft and defenseless). I was, therefore, fortunate in having the opportunity to observe a female with her young in an aquarium. I came across her while she was traveling overland (they do this on occasion) between ponds at the Prospect Park Zoo in NYC. In typical crayfish fashion, several dozen young clung to the swimmerets (feathery organs) on her underside. (Note: the red swamp crayfish is native to the southeastern USA but widely introduced elsewhere. Non-native crayfish cause serious problems in many parts of the world – please do not release unwanted pet crayfish).

Established in a 5 gallon aquarium, the female soon became quite bold and allowed me a peek at her version of maternal care. Any disturbance caused her to rear up, claws extended towards the threat – she definitely seemed more aggressive than crayfish I had kept in the past. The young remained on the swimmerets for over two weeks and then began making short feeding forays on their own but, to my surprise, returned unerringly to their mother after eating. At this point they also began to scamper about the rest of her body, sometimes covering most of her head from view. Knowing of this creature’s pugnacious disposition, I wondered when her “patience” would reach its limit. That limit came after about three weeks, when she promptly began devouring the prodigy she had so carefully nurtured until then. The survivors took refuge in the hiding spots (cracked clay flower pots) that I had provided for them, after which I moved the group to a larger aquarium.

A number of crayfish species are readily available and do well in aquariums. Particularly interesting are stream-dwelling forms, such as the red-tip crayfish, Orconectes erichsonianus, which seem determined to re-arrange every stone in their tank in an effort to establish the perfect home. Others you might consider are the P. alleni, a blue strain of which has been developed for the pet trade, dwarf species such as O. compressus, and the bright blue Australian yabbie, Cherax quadricarinatus.

I’ll write again soon and highlight other species. Until then, I’d appreciate hearing about your own experiences.

A good deal of interesting information, including a key to help you identify the crayfish you may come across, is sponsored by the Carnegie Museum of Natural History:

Thank you, Frank.

African Clawed Frogs – the uncommon origin of a common pet

African Clawed Frog
I’d like to welcome Frank Indiviglio back to That Fish Blog for another interesting post. Although they’re amphibians, we’ve seen so much of the African Clawed Frog in the aquarium trade, I thought this was appropriate here. Enjoy!

I’ve always been interested in the process by which a species becomes established as a pet. Interesting stories abound, none more so, perhaps, than that of the African clawed frog, Xenopus laevis. Hailing from southern Africa, female clawed frogs were (somehow!) found to possess an unusual trait – exposure to a pregnant woman’s urine causes the immediate release of the frog’s eggs! Dwelling in a harsh habitat, females must be ready to breed on short notice, and nearly always have eggs ready to be fertilized. This, combined with the ease of maintaining them in the lab, soon led to their widespread use in the Hogben Pregnancy Test.

Millions of these frogs were imported to the US in the 1940’s, with many finding their way into the pet trade. Unfortunately, they also made it into local waterways, and today are well established in several states, including Texas, California and Arizona. Ravenous predators, clawed frogs have been implicated in the declines of a number of invertebrate, amphibian and fish species. Recent research also indicates that this species may responsible for starting the worldwide Chitridiomycosis fungal epidemic that is threatening scores of amphibian species.

Feral populations of African clawed frogs are also to be found in Mexico, Chile, France, Italy, Java, Japan, Indonesia, Great Britain, the Ascension Islands and elsewhere. Despite the species’ origins in warm fresh water, one population has adjusted to life in the underground wells of a castle in England, where the water rarely tops 50F, while another group thrives in brackish ponds (they tolerate 40% seawater) in Orange County, California.

These tongue-less, claw-bearing, aquatic frogs make fascinating pets (they are, however, illegal to own in some states). One kept by my frog-enthusiast mother attained 21 years of age, and the published longevity record is 30 years. Unlike most frogs, they will accept non-living food, and thrive upon Reptomin food sticks and frozen fish foods. I’ll discuss the care of clawed frogs and their relatives, African dwarf frogs, Hymenochirus spp. and Surinam toads, Pipa spp., in a future article. Until then, please write in with your questions and observations. Thank you. Until next time, Frank.

You can learn more about this frog’s spread into non-native waters at:

Thanks again for the great article Frank! If you’re interested in reptiles or birds, Frank also contributes to That Reptile Blog and That Avian Blog.

Until Next Time,


Uncommon Facts About Common Aquarium Fish

I’d like to take time to welcome Frank Indiviglio to That Fish Blog. Frank is a former Bronx Zoo Zoologist, author and conservationist who’s worked with everything from fish to elephants. He’ll share his unique insights and work with various species on here, as well as the newly created That Reptile Blog & That Avian Blog. Welcome Frank!

Today I would like to pass along some interesting facts concerning fish you may be familiar with. I’ll focus mostly on aquarium trade species, with a few others added for good measure. I’ll add to the list in future articles. Enjoy, and please share your own store of unusual facts with us.

Finding a mate in the dark, featureless expanses of the deep sea poses quite a difficulty. Male benthic anglerfishes, such as Ceratias uranoscopus and related species, solve this dilemma by biting onto the first female they encounter. Thereafter, the male’s internal organs degenerate and he remains fused, by his mouth, to the female – surviving on nutrients circulating in her blood and periodically releasing sperm to fertilize her eggs!

Unique among the world’s fishes, male sticklebacks (small fishes of the family Gasterosteidae that inhabit marine, brackish and fresh waters), use kidney secretions to glue plant materials together when constructing their enclosed, bird-like nests. This behavior, along with their zealous protection of the eggs, helped spur the development of the aquarium hobby in Europe in the 1700s.

Cichlids found in Africa’s Lake Malawi are among the most enthusiastic of nest builders. Although measuring but 6 inches in length, males of one species create circular sand mounds that can exceed 3 feet in diameter, while another excavates 10 foot wide pits. Up to 50,000 such structures may be constructed in the same general area by a displaying group, or “lek” of males.

Marine damselfish, such as Stegastes nigricans, are unique in practicing a form of underwater “farming”. Pairs form territories around beds of marine algae (“seaweed”) and drive off fishes, shrimp, crabs and other creatures that show interest in this favored food.

Clownfish, such as the commonly kept percula clownfish, Amphiprion percula (or its cousin, the false percula, A. ocellaris, of “Nemo” fame) live unharmed among the tentacles of sea anemones — marine invertebrates that sting and consume other similarly-sized fishes. Anemone tentacles respond with a sting upon contact with any alien body, but are prevented from stinging themselves by chemicals in the mucous that they secrete. The clownfish, it seems, produces the same chemical in its own mucous and hence is not recognized as food.

Fishes lack external ears but do have inner ears that pick up the water pressure changes which accompany sounds. Aided by the Webarian Apparatus, an organ that connects the
inner ear to pressure-sensitive gas in the swim bladder, species such as carp and goldfish hear quite well and can communicate through vocalizations (perhaps it is not so odd to talk to your pet after all!).

Among the animals that are kept by people for their fighting abilities, none are as small as brackish-water fishes known as wrestling halfbeaks, Dermogenys pusilla. These thin, 3 inch-long warriors are the subject of staged matches in betting parlors throughout Thailand and Malaysia. Fights rarely result in injury, except to the wallets of losing bettors!

Despite popular belief, koi, Cyprinus carpio and goldfish, Carassius auratus, are not closely related. Goldfish, the first of any fish to be domesticated, were first kept by the Chinese over 2,000 years ago. Koi (the word means “carp” in the Japanese language) originated in the Black Sea area and arrived in Japan as a food source. They were first bred for domestic traits in Nigata, in northeastern Japan, in the 1820’s.

Ichthyologists discover new facts about fish on a near-daily basis. You can read articles about their findings at:

Thanks Frank,

Until Next Time,


Free Seminars at That Fish Place 2008 Anniversary Sale April 19 and 20th 2008

Here at TFP we are rapidly approaching our annual spring sale event, This year marks our 35th anniversary. For those of you who have made the trip for past years events, you know what a fun and crazy sale it is. If you have never been to one of our anniversary sale events, then this should be your year to check it out. There are thousands of items on sale, some of them at unbelievable savings.

One of both ours, and our attendees, favorite parts of our sale events are the free seminars. This year we have a great cast of speakers for your enjoyment. We are proud to welcome back Anthony Calfo, Steven Pro and Jesse Rothacker, all of whom have been guest speakers for us in the past. This year we have a couple of new speakers, Chris Brightwell and Doug Dent.
Here is a little information about each speaker, and the topics of their seminar.

Anthony Calfo:
Aquarium Photography Tips (Sunday 2:30 p.m.)

For those of you who are not familiar with Anthony, you are in for a real treat. Anthony has an incredible amount of information and enthusiasm for the aquarium hobby, and he spends a great deal of his time sharing his knowledge and experiences with hobbyist around the world. Anthony has authored, or co-authored, several books, the most recent of which is his second edition of The Book of Coral Propagation. Anthony also publishes C the Journal, magazine for aquatic science, travel, and adventure.

Anthony’s seminar this year is about aquarium photography, in which he will share some of his tips and tricks that he has learned through the years. Aquarium photography is something that many people struggle with (myself included), this seminar will hopefully help make better photographers out of us all.

Steven Pro :
Greenhouse Coral Propagation Farm (Saturday 10:30 a.m.)
Responsible Reef Keeping (Sunday 1:30 p.m.)

Steven Pro, yes that is his real name, has over the last 15 years turned his love of the aquarium hobby into his livelihood. Steven has operated an aquarium sales and maintenance company in the Pittsburg area for many years, as well as held several interesting positions within the industry. Steven has held positions on the board of directors for the AMDA (the American Marinelife Dealers Association) and the Pittsburg Marine Aquarium Society (Hosts of MACNA XIX in 2007) For those of you who have visited the website, you may also recognise him as a past member of the Wet Web Media crew.

Steven is performing two seminars for us this year. Saturday, Steven will chronicle his ongoing Coral Propagation greenhouse project. Over the last couple years Steven has been planning and building a Coral Farm, with the ultimate goal of large scale coral production for distribution. Steven is well into the project, and has already started to produce farmed coral.

Steven’s second seminar on Sunday will be on responsible reef keeping. This seminar will deal with issues that the worlds coral reefs are facing, and the impact that we as hobbyists have upon them. The discussion will involve focus on things that we as hobbyist can do to minimize our impact, and help ourselves at the same time.

Chris Brightwell :
Reef Aquarium Husbandry; Philosophies and Results. (Saturday 12:00 noon)

Chris Brightwell is a fellow graduate of Coastal Carolina University, and a rising name in the aquatics industry. Chris has authored numerous articles and books, including his latest book Marine Chemistry. In 2007 Chris launched a new company, Brightwell Aquatics, which offers a comprehensive line of water conditioners and supplement for Marine, Reef, and Freshwater aquariums.

Chris’s seminar will focus on the wide range of approaches and techniques that have been used in the maintenance of marine reef aquariums, and the theories behind these practices. Chris has done extensive research in the field of aquarium chemistry, both while working for Kent Marine in the past, and for product development and testing for Brightwell aquatics.

Doug Dent:
Aquarium Care Basics (Saturday 3:00 p.m.)

Doug has worked in the aquatics industry for over 30 years and is the V.P. of sales, and technical support for Ecological Laboratories, the manufacturer of Microbe Lift products. Doug is an expert in biological processes in aquatic environments.

Doug’s seminar will be about basic water chemistry, and biology, of aquariums and ponds. He will cover how the Microbe Lift products work, and how you can reduce your maintenance in both aquariums and ponds, where algae, ammonia, nitrite, nitrate come from, how to control, and how to cycle a pond or aquarium in 24 hours.

Jesse Rothaker :
Forgotten Friends Reptile Sanctuary (Saturday 1:30)

Jesse, is a herpetologist and founder of “Forgotten Friend” Reptile Sanctuary, a non-profit local reptile rescue based out of E-town. He gives hundreds of reptile shows and informational seminars to local groups and schools, and educates people on the responsibilities of being a good pet owner.

Jesse’s seminar will be a reptile show featuring all this stuff, along with a bunch of reptiles, including many Jesse and Forgotten Friend has rescued. His website is

I hope that this information has peeked your interest, and you will come to our anniversary sale to see this great group of speakers

Until next blog


Adverse Mutations in Blue-Tipped Acropora

In the interest of science, Dave asked me to post some biology/aquatics breakthroughs recently discovered here at That Fish Place. We hope that the information provided allows other aquarists and scientists to continue what we’ve started.
Thanks, Melissa

It all started with our recent shipment of Blue-Tipped Acropora, Acropora sp. For those readers not familiar with coral, this is one of the most easily recognizable, most beautiful corals in the aquatics trade. Unlike most corals in the trade, these were asexually reproduced and shipped here from a local coral greenhouse. Upon arrival, we began our normal quarantine process; placing the frags in an aquarium containing conditions identical to the display tank they would eventually inhabit. Remarkably, right from the beginning we started noticing differences in this batch…. click here to read the rest of the story and view pictures.