That Fish Blog – Aquarium Advice and Information

GloFish 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 »

 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.

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 »

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.

Unfortunately, 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 »

The choices for lighting your aquarium have never been so vast. Whether you are setting up a new aquarium, replacing an old light fixture, or adding to your existing light, there are many decisions to be made.  New technology, and improvements on older lighting methods, provide today’s aquarium hobbyist with a dizzying array of lighting choices for any aquarium. So, how do you choose? What is the best light for your aquarium?

Here are a few questions to ask yourself, to help you with the decision:

Is the light that you are looking for only going to be used on your current aquarium habitat, or are you planning on a more advanced aquarium in the future that may require a higher output light source? You may want to consider a stronger light than you need for your current livestock, as basic lighting may limit what you can keep in the tank down the line.   Read More »

Hello, Frank Indiviglio here.  The world’s 30-35 freshwater sunfish species (Family Centrarchidae) range throughout Canada, the USA and Central America.  Although popular among European aquarists, sunfishes have been largely been neglected in American aquaculture. This is a shame, as all are colorful, interesting and active, and most adjust well to aquarium life. From the tiny Black-Banded Sunfish to the 39 inch long Largemouth Bass, there is something for everyone.  I’ve had the good fortune of working with a “sunnies” ranging from the tiny Black-Banded Sunfish to the massive Largemouth Bass, and would enjoy hearing from readers who have also come to know them, or wish to (please post below).

Obtaining Sunfishes

Although rarely offered in the pet trade, many species are easily collected via seine net or minnow trap (check state regulations).  While their diversity is greatest in the southeastern USA (my friend in Louisiana collected 8 species in the lake behind his house!), sunfishes can be found most everywhere in the USA. New York, where I reside, is home to 14 species. Read More »