Freshwater Fish and Fishkeeping Quiz

Answer: Zebra Danio

The Zebra Danio is widely studied to unravel vertebrate development. In a segment of "Scientific American Frontiers," actor Alan Alda visited a lab with 150,000 Zebra Danios to discuss the gene-sequencing project. Endler's Livebearer is a close relative of the familiar guppy.

Answer: Gambusia, the mosquitofish.

The rapidly reproducing Gambusia affinis is still being introduced in waters where it's not a native, to control mosquitoes-- sometimes with devastating results to rare endemic fishes. "Barbus viviparus" was a biologist's gaffe; the fry in its body cavity had been a last meal! All of our native darters are oviparous ("egg-layers").

Answer: White Clouds

The revered Pai-yun Shan translates as "White Cloud Mountain," which the fishes' scientific name simply retranslates into Latin, as Tanichthys ("Mr. Tan's fish") albonubes ("White Cloud"). "Lower slopes" might have given it away. Though "good" might have the ring of ancient myth, the discoverer, Mr. Tan, was a scout troop leader. Would you really call Gyrinocheilus aymonieri, the Chinese Algae-Eater, a beauty?

Answer: omnivore

A detritivore eats semi-decayed detritus: so, would a "dentivore" eat other fishes' teeth? A piscivore specializes in eating other fish. An omnivore eats a little of everything. While a Loricariid will happily eat vegetation, they also like a meal of bloodworms and the like, making them omnivorous.

Answer: It is spawning.

Unlike conventional egg-scattering rasboras, our Harlequin Fish deposits a few sticky eggs at a time on the underside of a broad leaf, where egg predators may not notice them. This soft water southeast Asian enjoys the softest, salt- or other electrolyte-free water you can provide. Water retention, often a terminal symptom, can make a fish lose its balance. or even float at the surface. Fish suffering from gill parasites often "flash" their belly as they turn to rub their inflamed gills on a hard surface.

Answer: Dactylogyrus flukes.

The skin and gill flukes are several species of all-but-microscopic parasitic flatworms. The other pests are two ciliates and Piscinoodinium, a flagellate that can do a little photosynthesizing to keep it going while it searches for a host.

Answer: diatomaceous earth.

Fine-grained diatomaceous earth polishes the water to brilliant clarity but rapidly clogs, and you discard it. It's purely a mechanical filter, filtering minute particles. Fresh carbon adsorbs dissolved pollutants as a "chemical" filter but soon develops a bacterial biofilm and so becomes part of the biofilter.

The undergravel filter always combines mechanical filtration with extensive surfaces for bacterial biofilter. Hydrogen peroxide is a powerful oxidizer, but not a filter in any sense.

Answer: live baby guppies and other living food.

The Leaf Fish, Polycentrus schomburgki, will only strike at small living fish. Disguised as a brownish floating leaf, even to an extension on its lower jaw like a leaf stem, it drifts towards its prey. Then its huge, extensible mouth opens, and the small fish is sucked in.

Answer: all of these

These laterally-flattened and widely-distributed New World cichlids are all closely related, in the sub-group called "Heroine" cichlids-- more "like the genus Heros" than "like Jane Eyre," eh. Though their exact relationships are being challenged and discussed, the "Heroine" tribe are generally considered to include also the many Central American cichlids that you might still think of as "Cichlasoma" species.

Answer: that it is becoming naturalized in Florida's Everglades.

The few Endler's Livebearer, Poecilia species, first released on the market were all males, so the temptation has been to breed them with guppy females. The small coastal lagoon where they were first discovered has been partially filled. The species has not yet been reported from Florida's waters, where many other tropical fish have become feral intruders.