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Contains articles featuring information, advice or answering questions regarding aquarium fish and other livestock.

Aquarium Salt Mixes – Choosing the Right Salt for Your Tank

Juvenile Queen AngelChoosing the right aquarium salt mix to add to your tank can be can be a confusing process, especially if you’re new to the hobby. But, it isn’t as complicated as it may seem, you just need a little background info to get you on the right path to choosing the salt that is appropriate for your set-up.  

Salt in Freshwater Aquariums

Adding salt to a freshwater aquarium is not a necessity, but it is used by many aquarists as a treatment to add electrolytes to the aquarium water, and as both a stress reducer and a parasite deterrent. Basic Aquarium Salt is not the same as the formulated mixes used to make a brackish or saltwater aquarium. Aquarium Salt is simply Sodium Chloride, and does not contain minerals and trace elements like calcium and iodine like sea water mixes. Adding small portions of this salt can help to treat osmoregulatory stress, an imbalance or disruption in the exchange of salts and minerals between the fish itself and its environment. Stressful situations such as transport, disease, or injury can cause osmoregulatory stress, but if used properly, aquarium salt can increase blood and oxygen flow through the gills, helping the fish relax and heal. When used in higher concentrations for short time periods as a dip or bath, salt can help to build a the protective slime coat on the body, preventing parasites from attaching and even killing one-celled parasites like Protozoa, that may already be on the fish. While aquarium salt does have some benefits, it is not a necessary additive. Once introduced to the tank, salt does not evaporate out of the tank. It can only be removed with water changes and plants, inverts and other sensitive species may be negatively impacted if the concentration is allowed to rise. Read More »

GloFish – It’s All in the Genes

Electric Green Tiger BarbsGloFish are some of the most popular, colorful and controversial fish to enter the aquarium trade in a long time. Their easy care, small size, peaceful nature and neon bright colors make them appealing to aquarists of all ages, but the modifications that cause these bright colors cause some debate among aquarists, scientists and environmentalists alike.

The original “GloFish” were not created for the aquarium trade. They came from a popular fish used in many different fields of research, the Zebra Danio (Danio rerio). Zebra Danios have been used in research for environmental studies, cancer research, genetics, reproductive biology, neuroscience and applications to other fields as well. They even made the trip to space in 1975 on the Russian “Salyut 5” space station. So what makes them such good research subject? Zebra Danios are easy to breed and it only takes hours for the internal organs to develop after the eggs have been fertilized (about 24-36 hours, depending on temperatures and conditions). During this time, it is easy for researchers to monitor the development of the embryo since the “shell” around the eggs is a clear membrane. The eggs can hatch about 12-36 hours after that (again, depending on the conditions). These variable time frames also mean that, while the development is being studied, conditions can be adjusted to slow down or speed up the development, depending on what exactly the researchers are trying to determine. The genetic sequence involving the structure of the Zebra Danio’s DNA and RNA is very well-known at this point and is comparable enough to our own that, by understanding how changes in this structure affect the fish, researchers are gaining more understanding into how changes in our genetic structure can affect our own health.

Originally, GloFish were being developed for two major fields: cancer research and pollution detection. In the late 1990’s/early 2000’s, researchers thought to develop a fish that would change colors when a certain pollutant was found in their water. The thought was to develop a fish that would appear normal in “ideal” conditions but when a specific chemical or type of chemical was present in the water, a “trigger” would be set off to cause the fish to “glow” with a fluorescent protein in their bodies. As a step in this direction, they began to develop a fish that would always have this flourescent “glow” in a reproducible and hereditary way that wouldn’t affect the ecosystem around them. To do this, scientists turned to a fluorescent protein naturally found in jellyfish, corals and anemones rather than potentially harmful chemical dyes. Around the same time, similar projects were using a fluorescent protein to “mark” specific genes that were thought to be a cause or sign of cancer. By pairing the fluorescent protein with the cancer-related gene, researchers could see the fluorescence increase or decrease along with the other gene and see if an increase or decrease in that gene was related to the cancer. Since the genes (and cancers) in these fish behave in much the same was as they do within ourselves, researchers are using this to develop a way to track, diagnose and treat cancer in people. Read More »

The Freshwater African Butterfly Fish – Care, Breeding, Behavior

 In habits, appearance, and evolutionary history, the African Butterfly Fish, Pantodon buchholzi, is one of the most unusual of all aquarium species.  Yet despite having been in the trade for over 100 years, this “freshwater flying fish” (a misnomer, see below) gets little attention.  Captive breeding is challenging but possible, and its fantastic hunting behaviors are thrilling to observe.  I helped to set up an African Butterfly Fish exhibit at the Bronx Zoo, and was not at all surprised when it became a great favorite.  Most of the visitors I spoke with were astonished to learn that such an “exotic” creature, worthy of a large zoo exhibit, was available at many pet stores! 

Description

The yellowish-green to silvery-tan body is marked with an intricate pattern of speckles and lines.  The huge pectoral fins, reminiscent of those of marine flying fishes, lend an uncanny resemblance to a dead, floating leaf when viewed from above.  Long rays extending from the tail and the pelvic fin add to its remarkable camouflage.

FW Butterfly Fish

Uploaded to Wikipedia Commons by Toniher

The African Butterfly Fish’s mouth is noticeably upturned, an adaptation for feeding on insects at and above the water’s surface.  Less noticeable is the mouth’s large size and the many teeth it bears; although it tops out at 5 ½ inches, this specialized predator can take quite sizable insects and fishes.

Utilizing its wing-like pectoral fins and unique musculature, the African Butterfly Fish can explode from the water’s surface to snatch low-flying dragonflies, moths and other insects, and to escape predators.  It does not, as far as we know, glide above the water as do marine Flying Fishes (please see photo). Read More »

The Best Foods for Freshwater Aquarium Fish – Canned Freshwater Shrimp and Invertebrates

Shrimp of various species play an important role in the natural diets of many freshwater fishes, and the nutrients they supply differ from those found in insects and other more commonly-used aquarium foods.  Many native and exotic fishes under my care at home and in zoos prefer shrimp to all else, and do well when they are added to the diet.  And while ocean krill (not a true shrimp) is readily available, I wonder about the long range effects of feeding a marine animal to freshwater fishes.

tp53048Unfortunately, freshwater shrimps are difficult for the average aquarist to procure. I was, therefore, pleased when Zoo Med began offering canned freshwater shrimp.  Although marketed as a reptile food, I have fed canned shrimp and find them to be some of the best foods for freshwater aquarium fish, showing great results.  But I’ve been remiss in spreading the word among my hobbyist friends…if you decide to give them a try, please post your thoughts below, thanks.

An Important Consideration                                                                         

Small, whole animals are used in Zoo Med’s canned freshwater shrimp product.  This is preferable to offering our fishes small pieces of food market marine shrimp, which are usually missing nutritionally valuable internal organs (note: food grade shrimp are fine to use on occasion). Read More »

Archerfish Care – Incredible Brackish Water Insect Snipers

Banded ArcherfishHello, Frank Indiviglio here.  In the early 1980’s, I had the good fortune of being chosen to help set up the exhibits in Jungle World, a new Bronx Zoo building highlighting Southeast Asian wildlife. Leaf Insects, Sunbirds, Marsh Crocodiles, Giant Soft-shell Turtles, Proboscis Monkeys, Tapirs…all came under my care, but it was a mangrove marsh exhibit that became my favorite. It housed a variety of unique animals, including Mudskippers, Fiddler Crabs and Monos, but the real stars were a school of Banded Archerfish (Toxotes  jaculatrix).  Visitors especially enjoyed watching me service the exhibit…the Archerfishes would invariably squirt water at the movement of my eyes as I looked down at them, and they never missed!

Natural History

Seven archerfish species have been described. They range from India to Malaysia and Australia, ofrten in association with brackish water mangrove swamps, but most also enter freshwater and the ocean. Archers and other species that move between salt and fresh water for other than breeding purposes are known as amphidromous fishes. 

At least 1 species, the 5 inch-long Smallscale Archerfish (Toxotes microlepis), spends most of its time in the freshwater. The giant of the genus is the 16 inch-long Largescale or Spotted Archerfish (T. chatareus). Both occasionally appear in the pet trade, where they are often confused with the Banded Archerfish (please see below). Read More »