That Fish Blog – Aquarium Advice and Information

Hello, Frank Indiviglio here. Sticklebacks hold a special place in fish-keeping history – their fascinating breeding habits are credited with inspiring the development of the aquarium hobby in Europe in the 1700s.  The Sea Stickleback (Spinachia spinachia) is one of the group’s few marine representatives, and a good candidate for one of the most fascinating fish breeding experiences imaginable.

The Sea Stickleback is native to the cool waters of the Northeastern Atlantic Ocean, along the coast of Northwestern Europe.  One of the larger sticklebacks, it attains a length of 8 inches or so and is quite hardy in the aquarium. It stays along the coast, rarely straying into depths exceeding 15 feet.

Underwater “Bird Nests”

Male sticklebacks construct tiny nests consisting of plant material held together by secretions from the kidneys.  Clad in vibrant breeding colors (sea sticklebacks sport bronze and silvery bars and silver-yellow abdomens) they then display for the females, who lay their eggs within the nests.  Females have been shown to preferentially choose water flowing from nests of unmated males, even when kept out of sight of the nests.

The brooding male guards the nest from any and all intruders, exhibiting aggressiveness that is far out of proportion to their size.  I once observed a male three spine stickleback (Gasterosteus aculeatus) chase off a cunner that outweighed him a hundred fold.

Diet

In common with their relatives the seahorses, sticklebacks prefer live foods such as brine shrimp, blackworms, Mysids and Daphnia.  I’ve had some individuals take frozen foods, but such is by no means a certainty for all. I’ve found that sticklebacks seem to require quite comparatively large amounts of food, and lose condition rapidly if not fed adequately. 

Sticklebacks are fairly slow feeders, and will be out-competed by active species.  They are also quite pugnacious and prone to “fin nipping” their less agile neighbors.  Marine species get along well with spider and hermit crabs, small puffers and sea stars. 

Spawning Sticklebacks in the Aquarium

We are indeed fortunate that such unusual fishes are rather easy to breed…watching them do so is a treat rarely afforded those who study marine fish.  Although quite territorial, small groups will co-exist if enough nest sites are available.  Be sure to provide widely spaced groups of sticks and plants so that nesting pairs may have the privacy they require. 

Several species will come into breeding condition if their water temperatures are allowed to fluctuate with the seasons, i.e. by keeping them in an unheated tank in a room that experiences seasonal temperature variations.  You should also seek to provide a light cycle tuned to that they experience in nature.  

Native Sticklebacks

Unfortunately, like many temperate species, Sticklebacks get very little attention from aquarists these days. 

The Sea Stickleback is not readily available in the USA, but a number of other species can be collected here and kept in a similar manner.  I have had good luck in breeding the Three-spine Stickleback (Gasterosteus aculeatus) in a densely planted marine aquarium.  This species is usually described as a brackish water fish, but those I collected from the Great South Bay on Long Island, NY thrived under typical marine aquarium conditions.

Further Reading

An informative account of stickleback collecting and breeding is posted at www.glaucus.org.uk.

Please write in with your questions and comments. 

Thanks, until next time,

Frank Indiviglio.

Ninespine Stickleback image referenced from wikipedia and originally posted by Dryke.
Sea stickleback image referenced from wikipedia and originally posted by Visviva.
 

Hello, Frank Indiviglio here. Among the 150+ species of catfish classified in the genus Corydoras, all native to Central and South America, we find some of the most beloved of all aquarium fishes. Yet despite their willingness to breed in captivity, not many aquarists make the effort. As we will see, however, the droll cory cats employ one of the fish world’s most unusual breeding strategies…they are definitely worth a closer look!

Startling Reproductive Behavior

Female cory cats are larger than males, and their body has a thicker, more rounded appearance. In some species, the male’s dorsal fin is thinner and higher than the female’s and is held in a noticeably more erect position.

Corys may breed in either pair or group situations. Males chase gravid females, with the pair eventually lying motionless and perpendicular to one another (this is known to aquarists as the ‘T-Position”). The male lies on his side, and, amazingly, the female then uses her mouth to withdraw sperm from his vent.

Fertilization – Internal or External?

How fertilization actually occurs is still open to some discussion. Most ichthyologists believe that the sperm exits the female’s gills, and is shunted to a unique cup that she forms with her pelvic fins.

Upon obtaining the sperm, the female lays 1-5 eggs into this cup. She then moves off to a pre-cleaned site, usually a plant or the aquarium glass, where she glues each egg individually. She repeats this process with the same or another male until her clutch of 10-25 eggs is laid, an ordeal that may last 3-6 hours.

Some researchers have suggested that the sperm passes through the female’s digestive tract, to be released along with the eggs, or that the female expels the retained sperm upon the eggs. In any event, a most extraordinary means of fertilization…why such a strategy would evolve has not, to my knowledge, been explained.

Breeding Corydoras

While Corydoras cats may spawn spontaneously, the most consistent results will be obtained if cool, highly oxygenated water is added to the aquarium, simulating the drop in temperature and rise in water levels that accompanies the start of the rainy season in most Corydoras habitat. Dropping the aquarium’s water level beforehand may also help.

While various species differ in their requirements, the formula that I have used for bronze corys (C. aeneus) seems to work well in general. After dropping the water level for 2-3 weeks and maintaining it at 76 F, I add water of 60 F in an amount equal to 1/3 the volume of the tank.

Caring for Eggs and Fry

The eggs can be left in place and the adults removed (some are egg predators), or they can be carefully transferred to a rearing aquarium (they are fairly large and sticky for a day or so after deposition).

The fry should be housed in shallow water (3-4 inches) at first, as constantly rising to the surface for air will weaken them significantly.

Cory cats are, despite their “scavenger” reputation, highly specialized predators on tiny invertebrates. Their fry are best reared on live blackworms, brine shrimp and Daphnia, with animal-based flakes and pellets being added as they grow.

Plan to be in it for the long haul…a bronze cory in my collection is nearing 21 years of age!

Further Reading

Peru’s popular panda cory (Corydoras panda), described in 1969, favors cool, fast moving streams. To read more, please see

http://www.redorbit.com/education/reference_library/fish/panda_corydoras/2190/index.html.

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

Hello, Frank Indiviglio here. As fall arrives in the temperate zone, outdoor koi ponds will need some attention if all is to go well when the temperatures drop.

Basic Considerations

The metabolisms of both koi and the various bacteria that occupy the pond and filter slow down as temperatures fall. Your fish will not be as hungry as usual, and leftover food will not decompose as quickly as in the summer. Dead plants and other organic material in the pond may also remain more or less “intact” through fall and winter.

However, don’t be fooled by the relative “quietness” of this time….as temperatures rise in the spring, decomposition will begin and the resultant ammonia spike may kill your fishes. Therefore, take care to be extra vigilant in removing organic detritus from your pond as fall approaches.

Cleaning

Be sure that your pond filter is in good shape and running well…rinse or replace filter media and continue with routine backwashes.

If necessary, install a leaf cover or net. This is not merely an aesthetic consideration…decomposing leaves will rob water of oxygen, lower the pH and increase the ammonia level.

To control the amount of dead plant material that enters the pond, remove any aquatic or emergent plants that will not survive the winter.

Health Checks

It is especially important that your koi be in good health as the weather changes. Immune systems will be stressed by the falling temperatures, leaving the fishes open to illness and parasitic infection. Bacteria and fungi that are ever present, and may be of little concern to healthy fishes, will prove dangerous to those not in the peak of condition during the fall and winter.

Feeding

As fall progresses, switch your koi from high protein pellets to more easily digested foods or wheat germ based pellets designed for use in cool water. Do not feed your fishes when temperatures drop below 52 F.

Temperature

Make sure that heaters or surface de-icers, if required, are in good working order. If you utilize a heater, set its thermostat for 62 F. Koi will feed lightly at this temperature, but keep an eye out for leftovers. In unheated ponds, cease feeding at 51 F.

Further Reading

For optimistic readers already thinking spring’s arrival, please see our article Koi, a Matter of Extremes in Spring.

Please check out our koi and outdoor pond books for further information.

For interesting forum comments and photos dealing with overwintering koi under extreme weather conditions, please see the forum at koi-bito.com.

Please write in with your questions and comments.

Thanks, until next time,

Frank Indiviglio

Japanese water garden image referenced from wikipedia and originally posted by Solipsist

Hello, Frank Indiviglio here. Today I’d like to highlight some simple ways that you can become involved in hands-on research with marine animals. Next time we’ll take a look at programs designed for people interested in fishes.

Sea Turtle Research in Costa Rica

The Caribbean Conservation Corporation, founded in 1959 by legendary turtle biologist Archie Carr, was the world’s first marine turtle protection organization. Promoting conservation through research, and political advocacy, CCC is based in Florida, and its primary field station is nestled between rainforest and sea at Tortuguero National Park, Costa Rica. Volunteer researchers have always figured prominently in the group’s work, and today a number of interesting opportunities are available.

Sea Turtles, Jaguars and Frogs … My Experience with CCC

My first field trip to Tortuguero, working with green turtles and 1,500 pound leatherbacks, hooked me for life. I and other researchers tagged and measured turtles, counted eggs, and monitored nests.

I also participated in studies focusing on the area’s 300+ bird species and was lucky enough to see kinkajous, caimans, ocelots, tapirs, jaguar tracks (overlapping my own!), arboreal tarantulas, strawberry poison frogs and a host of other incredible animals.

Working with Seals

Seals of several species are becoming increasingly common in coastal urban areas, where they face threats from boat collisions, harassment and pollution-related diseases. The Seal Conservation Society maintains a comprehensive list of organizations that assist injured seals and provides information for those interested in becoming wildlife rehabilitators, beach monitors or “seal watch” tour leaders.

Untrained people should not approach seals – injured animals and females returning from hunting to claim their pups can be extremely dangerous. In the USA, sick or harassed seals can be reported to the local police or the National Oceanographic and Atmospheric Administration’s 24 hour emergency hotline: 800-853-1964.

Helping a Living Fossil

Most people do not realize that no intravenous drug produced in the USA reaches the market without first having been tested with a chemical produced by an ocean-dwelling relative of the spiders.

Compounds within the blood of the horseshoe crab (Limulus polyphemus) far surpass synthetics in detecting drug impurities. Biomedical companies draw blood from millions of these ancient (as in “unchanged for over 200 million years”!) creatures yearly. Although horseshoe crabs harvested for blood samples are released, coastal development and collection for the bait trade has caused US populations to plummet.

Based in the Northeastern USA, Project Limulus relies upon volunteers to monitor over 5,000 spawning horseshoe crabs each spring in an effort to help formulate conservation strategies.

Over 17,000 horseshoe crabs have been tagged by US Geological Service volunteers working along the Delaware Bay. Their work seeks to assist both horseshoe crabs and a shorebird known as the red knot. Undertaking one of the longest known bird migrations (Argentina to the Arctic), red knots somehow time a stopover on their trip to coincide with the spawning of the Delaware Bay horseshoe crab population. Red knots rely upon horseshoe crab eggs to fuel the last leg of their amazing journey, and have suffered massive declines since this food source has become scarce.

Further Reading

Please see my article Hands on Experiences in Sea Turtle Conservation for further information on working in Tortuguero, Costa Rica.

Well, that’s just the tip of the iceberg…please write in if you are interested in other research opportunities. I’ll cover fish-oriented programs in the future. Thanks, until next time, Frank Indiviglio.

Hello, Frank Indiviglio here. Although varying dramatically from one another in appearance and lifestyle, corals, jellyfishes and sea anemones are closely related. Classified within the phylum Cnidaria, both immobile forms (“polyps”) and mobile species (“medusas”) bear unique stinging organelles known as nematocysts, with which they capture prey and defend themselves (many are capable of delivering painful stings and should not be touched with bare hands). With over 10,000 species to choose from, the aquarist interested in Cnidarians will never be bored!

Jellyfishes

I first ventured into marine aquarium keeping at age 7, with a jellyfish I had captured. I provided it with fresh sea water daily, which likely supplied some food items. However, all glass aquariums were not yet available, and the unfortunate beast was poisoned, no doubt, by rust leaching from its tank’s metal frame.

Jellyfishes are increasingly exhibited and bred in public aquariums, but most are difficult to maintain at home. One exception is the upside down jellyfish, Cassiopeia andromeda, which is now available in the pet trade. In most “un-jellyfish-like” fashion, this species rests on the substrate with its tentacles trailing in the water above.

Much of the upside-down jellyfish’s food is produced by symbiotic algae, so intense lighting is necessary. It will also consume newly-hatched brine shrimp, but it cannot compete with fast moving aquarium fishes.

Coral

Until recently, corals were considered nearly impossible to keep in home aquariums. Water quality is exceedingly important, as is the wavelength and intensity of the lighting provided. Many corals obtain much of their food via the action of the symbiotic algae which live within them. Without proper lighting, the algae perish…additional food provided thereafter cannot keep the coral alive. Fortunately, a variety of commercially available lights and foods have now simplified coral husbandry (please see below).

Most corals feed upon plankton-sized food items. One exception is the popularly-kept tooth coral, Euphyllia picteti. This species readily takes pieces of shrimp and other large foods, and its appetite is therefore easy to satisfy.

Until recently, over-collection was a leading clause of coral reef destruction. Although collecting is now outlawed in many areas, please be sure that any coral you purchase is commercially cultured, as is our stock at ThatFishPlace/ThatPetPlace.

Sea Anemones

Sea anemones are well-suited for aquarium life, although most perish quickly if kept in sub-optimal water quality or without a steady current of water flowing over them at all times. Sea anemones and the clown fishes that often shelter within them make for a beautiful and interesting display.

The white, brown or pink Caribbean anemone (Condylactis gigantea) is quite hearty but is rarely adopted as a home by clown fishes. More attractive to these popular fishes is the purple-based anemone, Heteractis magnifica. This anemone is unusually active, and quite frequently travels about the aquarium.

Anemones will thrive on weekly or twice weekly meals of shrimp, clam, fish and similar foods.

Useful Products

Please check out our metal halide bulbs, T-5 fluorescent bulbs and filter-feeding invertebrate foods, all of which have greatly simplified the captive care of corals and their relatives.

Further Reading
For further information on keeping jellyfishes, please see our article The Upside-down Jellyfish in the Home Aquarium.

Please also check out our extensive line of coral propagation and reef books.

To read more about the natural history of Cnidarians, please see
http://www.earthlife.net/inverts/cnidaria.html.

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