That Fish Blog – Aquarium Advice and Information

Hello, Frank Indiviglio here.  Anyone with an outdoor swimming pool is aware of the vast numbers of insects that continually crawl into or alight upon the water.  If you now consider how many billions of terrestrial insects find their way into the world’s fresh and marine waters each day, you will quickly realize that fishes have ample opportunity to consume a food item that is not usually included in captive diets (and lets not forget about the millions of aquatic insect species).  Small wonder that earthworms, crickets and waxworms are among the most effective fishing baits known.

An Overlooked Resource

However, while the sale of live and canned insects to reptile owners has long been a booming business, aquarists have largely disregarded insects as a food source for fishes.  Even well-known insect specialists such as African butterfly fishes (please see photo), mudskippers and archer fishes are rarely provided with the invertebrate-rich diets they favor.

My Introduction to Insects as Fish Food

I first became aware of just how much fishes favored insects quite by accident.  As a youth I constantly experimented with mixed species “shoreline” type aqua-terrariums…green treefrogs living on branches above guppies, bronze frogs with pumpkinseed sunfishes and so on. 

 I noticed that crickets which fell into the water were set upon ravenously by whatever fishes happened to be nearby.  Dead, water-softened crickets elicited a feeding frenzy among even the most “peaceful” of fish species, such as guppies, Cory cats, platys and swordtails.

Using Live and Canned Insects

I soon found insects to be eagerly accepted by many typical (and untypical!) aquarium fishes, including freshwater, marine and brackish species.  I continue to use substantial numbers of insects as food for a wide variety of fishes, and believe that the vigor, color and health of many has benefitted as a result.  Increased feedings of insects and similar foods may also be useful in bringing certain freshwater species into breeding condition.

  Canned invertebrates offer a convenient method of providing your fishes with valuable dietary variety.  Next time we’ll take a look at their role in fish–keeping and some other examples of insect-feeding among wild fishes.  Until then, please write in with your questions and comments.  Thanks, until next time, Frank Indiviglio.

Further Reading

The archer fish feeds almost entirely upon terrestrial insects, knocking them from vegetation with well-aimed jets of water.  By specializing so, it is able to exploit a unique food source in a habitat teeming with competing species.  The Friends of the National Zoo has posted information on their care in the zoo and natural history at http://nationalzoo.si.edu/Animals/ThinkTank/Animals/ArcherFish/default.cfm.

 
Please see also the following article on our blog – Archerfish: Aquatic snipers for husbandry advice.

Image refereneced from Wikipedia and originally posted by Toniher.

Especially for beginners, getting what you need for setting up a saltwater or reef aquarium can be daunting.  One of the most confusing aspects of the process may be Live Rock.  Here are some common Q & A that may make it a little clearer for anyone, especially those who just starting out.

Do I need Live Rock and what is its purpose?

Live rock is the calcium carbonate skeletons of ancient corals and other calcareous organisms, which forms the base of coral reefs.  It is not actually “alive” but is it is usually encrusted with coralline algae and inhabited by microscopic and macroscopic marine organisms.  The organisms on the live rock help to establish the biological base of the aquarium.  The rock serves as a biological filter hosting nitrifying bacteria that fuel processes like the nitrogen cycle to eliminate organic waste.  Live rock also has a stabilizing effect on the water chemistry, especially helping to maintain constant pH by releasing calcium.  The other obvious purpose is for decoration.  The rock, once established, serves as a shelter for fish and inverts, as a decorative element encrusted with colorful coralline algaes and other organisms (that may appear to spring from its surface from nothing), and as a platform for corals that you introduce to grow onto.

What is the difference between natural and cultured rock?

There are many varieties of live rock.  Most are named for the region where they are harvested, and often they have distinctive forms and characteristics. Some are dense, some are lighter and more porous, some are branchy, some are plate-like, ect.  They all basically serve the same purpose, and they may be mixed and matched according to your taste and needs.  Natural rock is chipped off and collected from specified areas in designated regions.  This rock is naturally occurring and highly variable.  Cultured rock is man-made from specially mixed concrete that is formed into basic shapes and then placed in the oceans near reefs for a period of 1-5 years where it is seeded with the same micro and macro organisms as natural rock. The rock is then collected and distributed for aquariums.  Cultured rock is favorable as it has the same benefits to the aquarium, but less environmental impact and is sustainable. It is typically less variable in shape.

How much rock do I need?

You may hear different opinions on how much rock you need, but it will depend on what your intentions are. Generally, the rule of thumb is 1-2 lbs per gallon.  This amount can vary depending on the arrangement you want and the density of the rock.  You may choose to purchase all the rock you need when setting up the tank initially, as the rock be used to cycle the tank, and will cure in the process.  Otherwise you can buy the rock a few pieces at a time, cure it in a separate vessel then add pieces periodically until the arrangement is where you like it.  The other option is to purchase base rock and cover it with fresh live rock.  Over time the base rock will be seeded by the live rock.  Just be sure your arrangement has spaces where the water can circulate through the rock and dead zones don’t occur.

What is curing and how do I cure rock?

Curing Live Rock means conditioning or cycling it for use in your aquarium. Cured rock has already been conditioned and is stable to use right away in an aquarium with minimal concern of fluctuations in water chemistry.  Fresh live rock is not cured and it shouldn’t be placed directly into a main aquarium until you cure it.  The collection and shipping process of most rock involves it being out of the water for days at a time, and a lot of the organic matter on the rock dies off.  By tanking and curing the rock, you allow the rock to recover from these stresses.  The dead matter breaks down and new beneficial organisms have the chance to re-establish and freshen up.  If you purchase fresh rock, a saltwater rinse or dip and shake will help to remove loose debris and some of the dead matter to kick start the curing process.  You can learn how to cure live rock in this short video.

How long will it take for stuff to start growing on my rock?

Once the rock is in the tank and the rest of your set-up is complete with adequate lighting, skimmer, and circulation, additives such as calcium, iodine and strontium will encourage the growth of colorful coralline algaes, and contribute to the health of other forms of live rock growth.  As the tank establishes and becomes more stable, you’ll probably see a variety of organisms from macroalgaes to small corals and other sessile inverts.  Each tank and each piece of rock may reveal different surprises, but the important thing is patience.  Taking the time for careful set-up and maintenance and a time allowance for the tank to progress at a comfortable pace will result in a healthy and sustainable reef environment.

Hello, Frank Indiviglio here.  The world’s oceans harbor a great many creatures that produce medically valuable compounds. Sessile marine invertebrates (those which do not move, but rather remain fixed in one location) seem to be particularly valuable in this regard.  In fact, sponges, sea whips, sea squirts and similar animals are the source of most of the invertebrate-derived medicines in use today. 

A review of the pharmaceutically active compounds isolated from sessile marine organisms shows that, while the animals themselves are quite different from one another, their shared lifestyle has fostered similar adaptations – the evolution of powerful chemical secretions.

 Protection for Immobile Animals

Animals which cannot flee from predators must devise alternate means of protection…an arsenal of protective chemicals, for example.  Also, the feeding mode utilized by many sponges and other sessile organisms – filtering seawater – brings not only food but also harmful pathogens and parasites into their bodies.  These are attacked with potent antimicrobial compounds.

 A suitable anchorage (attachment) site is vital to the survival of an invertebrate which is unable to move about.  Competition for such sites can be keen, yet immobile animals are again faced with the dilemma of being unable to physically exclude other animals.  Many have, therefore, evolved secretions that kill other animals. The composition and function of these various chemicals often lends them medicinal value as well.

Medically Important Marine Invertebrates

Sponges, the best studied of the marine invertebrates, and have given us Topsentin, an anti-inflammatory, and Lasonolide, which fights tumors by binding with their DNA. 

Brightly colored sea whips have yielded Pseudoterosin, which reduces swelling and accelerates wound healing.  Also known as gorgonians, several species of these soft corals do well in marine aquariums.

Tunicates, or sea squirts, evolved a primitive backbone, known as a notochord, over 540 million years ago, and are thus the earliest ancestors of modern day vertebrates.  These sac-like filter feeders produce Ecteinascidin,   a compound which blocks DNA transcription.  It is believed that Ecteinascidin may someday find use in treating breast cancer. 

Bryostatin, isolated from colonial marine invertebrates known as bryozoans, or moss animals, forces cancer cells to mature, thereby halting their ability to divide.  

A number of mobile marine invertebrates also produce chemicals that are of interest to medical researchers.  Cone snails, for example, secrete virulent toxins that have yielded the powerful pain killer Ziconotide.  This calcium channel blocker inhibits the relay of neurotransmitters and is used to treat people living with severe chronic pain.

Opportunities for Aquarists and Researchers

So, please don’t ignore the small, immobile creatures in your aquarium and the world’s oceans.  Your observations of their behavior can lead to unexpected and medically important discoveries.  For those of you interested in serious medical research, the world’s marine invertebrates offer unlimited possibilities, and the field is wide open.

Further Reading

The Harbor Branch Oceanographic Institution has posted an overview of some of the exciting work being done with medically useful marine invertebrates at http://www.informaworld.com/smpp/content~content=a713743150~db=all.

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

Hello, Frank Indiviglio here. Please see Part I of this article for information on using plants and bacteria to control algae. Today I’d like to take a look at some algae-eating fishes, snails and shrimps.

Sucker Catfishes (Plecostomus, Hypostomus, Loricarichthys spp.)
An incredible array of fishes consume algae, with these interesting beauties being among the best known. Larger sucker cats and Chinese sailfin sharks (see article below) can also be kept in outdoor ponds.

Thailand Flying Fox, Epalzeorhynchus kallopterus
This nicely marked fish consumes all types of algae, and is also fond of the flatworms that sometimes arrive in aquariums along with live plants.

Siamese Algae Eater, Crossocheilus siamensis
This fish is similar in appearance to other, less-effective species, and is sometimes sold as the “True Siamese Algae Eater”. It does well in schools, and consumes even the coarser varieties of hair and beard algae.

Chinese Hillstream Loach, Beaufortia kweichowensis
This small loach is one of my favorites. It has been compared to a flounder in appearance, but reminds me of the oddly-shaped torpedo rays.

This active loach is adapted to fast-flowing waters, and fares best in high oxygen environments. It is well-suited for removing algae from glass and plant leaves, and is rarely if ever bred in captivity…definitely a fish worth working with for those interested in breaking new ground.

Garra pingi pingi or Pingi Log Sucker, Discognathus pingi
Formerly rare in the trade, this stout East Asian bottom dweller has a huge appetite for algae of all types. Many aquarists find they must supplement its diet with algae wafers; those I have kept took pre-soaked kale as well.

This is another species which would make a nice breeding project, as only wild-caught animals are available at this point.

Algae Eater, Gyrinocheilus aymonieri
The “standard” algae control fish in smaller aquariums, the taxonomy of this interesting species is somewhat of a mystery. While typically reaching 4 inches in length, I recall receiving shipments of individuals that topped 11 inches. I hope to keep some in an outdoor pond in the future, to see if the increased water volume might spur additional growth.

Algae eaters relentlessly comb rocks, glass and plant leaves for algae, and will take leftover fish flakes as well.

Freshwater Shrimp
Almost all of the dozen or so species currently available favor algae as food. Particularly attractive is the cherry shrimp, Neocaridina denticulata sinensis. Given proper care (please see article below) they will breed prolifically, with a large group making for a spectacular display.

Freshwater shrimp will co-exist with the fish mentioned above, but will, however, be harassed or eaten by fishes with carnivorous tendencies.

Snails
A number of snails live almost entirely upon algae, but many consume plants as well. Apple snails can eat a surprising number of plants overnight, while olive Nerites (please see article below) take only algae and do not reproduce in fresh water. The Japanese trapdoor snail is also a good choice, but needs warm, well-filtered water.

Further Reading
To learn more about some of the creatures mentioned above, please see the following articles:
Freshwater Shrimp

The Chinese Sailfin Shark

The Olive Nerite

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

Hello, Frank Indiviglio here.  Among the Cichlids (Family Cichlidae) we find some of the most interesting and highly desirable of all freshwater aquarium fishes.  Nearly all show a startling degree of responsiveness to their environment and owners, with many becoming true “pets” as opposed to animals to be observed only.  Included among the group are Oscars, Jack Dempseys, angelfishes, convicts and other popularly-bred species, as well as a number about which little is known.

Diversity and Range

With well over 1,300 species named to date, and many as yet un-described, this family is one of the fish world’s largest. Ranging in size from 1 to 36 inches, Cichlids inhabit the fresh and brackish waters of Central and South America, the West Indies, Africa, Madagascar, Syria, Israel, Iran, southern India and Sri Lanka.  One species, the Texas cichlid, occurs in the USA.  Found throughout the drainage of the lower Rio Grande River, it is the most northerly of all cichlids. 

A number have been widely introduced, with Oscars (velvet cichlids) being long-established in southern Florida.  I have collected them in the Everglades, and have reports of a great many other introduced populations.

Parental Care

One near universal trait among the family is the amazing degree of parental care given the young. In many cases both the parents tend to the fry, cleaning them and the nest site and driving off potential predators.  The lovely, popular discus (Symphysodon aequifasciata), a native of the Amazon Basin, feeds its young with a modified mucus secreted from the skin.

The Unique “Second Jaws”

Cichlids have a second pair of jaws in the throat.  Known as the pharyngeal jaws, these unique structures process food and have freed the primary jaws to develop an amazing array of adaptations to deal with specific and unusual food items.  Included in this family are species that feed upon bacteria, other fishes, hard-shelled mollusks, algae and an amazing assortment of other food items. 

It is speculated that specialized adaptations have allowed cichlids to become the dominant fish family in many of the ecosystems in which they occur.

African Rift Lake Cichlids

 In Lake Victoria and other water bodies of Africa’s Great Rift Valley live a variety of cichlids that have all evolved from a very small number of “parent species”.  About 90% of these fishes are endemic to a single lake, and the speciation process seems to have occurred in the relatively short time.  Up to 200 closely related species, often termed “species flocks”, may be found in a single lake. 

I’ll cover the care of individual Cichlid species in the future. Until then, please write in with your questions and comments.  Thanks, until next time, Frank Indiviglio.

Further Reading

We have posted a number of Cichlid care articles on our blog.  For information on keeping the popular and aptly-named Red Terror, please see The Red Terror: Cichlid Species Profile .

Ed. Note: Lots of cichlids are featured on our catalog photo contest located on Facebook.  Take a look here and vote for your favorite.