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.

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.

Hello, Frank Indiviglio here.  I must confess that I like algae, perhaps because many of the creatures that I favor – shrimp, tadpoles, snails, loaches and others, do best in algae-rich tanks.  I’ve even encouraged algae to grow on the backs of aquatic snakes and turtles in zoo exhibits, much to the chagrin of the higher-ups! 

But, of course, algae certainly can get in the way of enjoying one’s pond or aquarium, and may endanger the health of the animals living therein as well.

Algae Diversity

Algae, which are not true plants, exist in a bewildering number of species.  For our purposes, we can roughly classify the commonly-encountered varieties as follows:

Green algae (hair, beard algae) thrive in well-lit situations.

Brown algae do well in low light.

Blue-green algae (actually a type of Cyanobacteria) and red algae live mainly in marine environments.

Controlling Algae

Nitrates and phosphates are the primary nutrients utilized by the most types of algae…limiting their concentration is the key to effective and safe algae control.

Algaecides and other “quick fixes”, while effective in the short term, do not address the root of the problem.  I always recommend that aquarists take the time to identify the reasons that algae has become established.  I have found this to be the most effective approach to algae control, be it in a betta bowl or a 77,000 gallon zoo exhibit.  And, because we learn much along the way and often utilize a number of fascinating animals and plants, the process is also very rewarding.

I’ll first discuss control methods that can generally be described as “natural” and will then mention a few more intensive alternatives.

Bacteria

The most effective algae enemy we might employ comes, surprisingly, in the form of another one-celled “non-plant/non-animal” – bacteria.  Many species consume the same nutrients as do algae, and can out-breed and out-compete even the hardiest types.

A number of species of beneficial aerobic bacteria (those requiring oxygen, which are also vital to water quality) will colonize gravel, filter media and other surfaces bathed in aerated water.  They will build up incredibly dense populations over an under-gravel filter, rendering it very difficult for algae to get a foothold. 

Nutrafin Cycle, which contains living bacteria, is especially effective in introducing these organisms to aquariums.  A number of other supplements, effective in fresh water and marine aquariums, are also available.

True Plants

Aquatic plants are very effective in capturing the nutrients needed by algae and limiting their growth.  However, many do not reproduce vigorously, so plantings should be as dense as possible.  In some situations, carbon dioxide supplementation and the use of plant food and iron might be useful.

Floating and emergent plants such as cattails and water hyacinth, lettuce, and lilies combat algae on two fronts – consuming nutrients and limiting light availability. 

If you are not ready to tackle aquatic plant gardening, you might consider using certain hardy terrestrial plants that thrive in water.  As long as their leaves can break the surface, peace lilies, pothos and aluminum plants will fulfill much the same role as true aquatic plants, and their root systems make for wonderful underwater effects.

Next time I’ll discuss how fishes, invertebrates and water additives can be used to combat algae.  Until then, please write in with your questions and comments.  Thanks, Frank Indiviglio.

Further Reading

To learn more about Cyanobacteria (“blue-green algae”), please see Aquarium Slime.

To read about adding beneficial bacteria to aquariums, please see my article Nutrafin Cycle.