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Breeding Sunfish

Think of them as the cichlids of North America.

By Robert Bock

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America is the land of opportunity, the saying goes. But for fish breeders, it's a land of missed opportunity. The U.S. is home to a vast array of nest builders and fry tenders that aquarists have overlooked and ignored. Many are drab, but a few have the brilliant colors that aquarists prize.

And all are fascinating. Sunfish excavate nests and rear their fry until they are free-swimming. Sculpins and many types of darters hide their eggs on the underside of rocks and guard them ferociously. The continent is also home to what may be the world's only nest-tending cyprinid — the fathead minnow, and the bullheads, arguably the world's most parental catfish.

In most cases, the breeding habits of native fish species have been observed only in the wild. Aquarium spawnings have been few and largely undocumented. While other aquarists travel to Africa or South America in search of novel species, the native fishes of the United States offer the chance to become an expert — a pioneer of sorts — literally in one's own back yard.

Sunfish Observations
For the past three years I've worked with the centrarchids, or sunfishes. This genetically diverse group of fish spans the U.S. and Southern Canada, ranging from the delicate Enneacanthus sunfish to hulking predators like the largemouth bass.

Distant cousins to cichlid fish, the sunfish number some 32 species, many of which have several subspecies. A few, like the blackbanded sunfish (Enneacanthus chaetodon), longear (Lepomis megalotis) and orangespotted sunfish (Lepomis humilis), make striking aquarium inhabitants. But after observing them close up, I believe that even run-of-the-mill species, like the green sunfish (Lepomis cyanellus), could provide the brood stock for captive bred strains that would rival even reef fishes in intensity.

The finer points of collecting sunfish and other native fish have already been covered in excellent articles in this magazine. I usually collect by seining the shallows of ponds and creeks, or by angling with small hooks. Before collecting any native fish, however, you should check with your state fish and wildlife agency to obtain the necessary permission, and to learn what regulations apply.

To date, I've been lucky enough to get two Lepomis species to spawn: the pumpkinseed sunfish (Lepomis gibbosus) and the longear sunfish. Many of these species are capable of reaching 8 to 10 inches in length, and are simply too large for all but the most spacious of aquariums.

It's best to avoid these full-size fish. Instead, find an over crowded pond with stunted individuals of no more than 4 to 5 inches in length. Both longear sunfish and orangespotted sunfish seldom exceed this size. Four or five such fish should then be given the run of a 55-gallon aquarium.

The males are first to enter spawning mode, in response to rising temperatures — beginning in the low 70s (Fahrenheit) — and longer day length — upward of 12 hours. A typical Lepomis male will begin by excavating a circular nest in the gravel. He does this by shimmying, blasting the gravel out of his way with the back and forth motion of his tail fin. Some Lepomis males will also nudge a collection of small stones into the nest after it has been excavated.

Just before nest building, Lepomis males will develop intensely bright colors. They will also become extremely territorial and extremely nasty. This will pose a problem for most of the other sunfish in the aquarium, unless they also happen to be equally nasty males.

Native Contributions

Aquarists who breed native fish can witness fascinating events that few have ever seen before. However, they also have a chance to make a significant contribution. Many of our native fish species are under siege, either threatened or endangered, due to pollution and habitat loss.

For example, although the blackbanded sunfish is not in trouble in New Jersey; it's listed as endangered in Virginia and in need of conservation in Maryland. The mottled sculpin, while abundant in the east, is rapidly losing ground in the Great Lakes Region to the round goby, an introduced species.

Captive-bred populations can provide a hedge against extinction, should the remaining populations of fish like the blackbanded sunfish and the mottled sculpin ever run into trouble. Similarly, information gained by breeding an abundant species like the mottled sculpin might provide useful information for future attempts to bring back endangered species, like the Shoshone sculpin (Coitus beldingi) or the Paiute sculpin (Coitus greenei).

American aquarists have already made important contributions to the survival of species in other parts of the world. Their skills and expertise would also be invaluable here at home.

Betta-like, Lepomis males will often drive intruders away by flaring their gill covers. To augment the display, each Lepomis species has either an extension or a prominent marking on the gill covers, ranging from the ear-like projections of longear and redbreast sunfish, to the bright red dots of pumpkinseeds.

Females need slightly higher temperatures to ripen — in the high 70s. To prevent them from being injured, it's advisable to install a glass partition between the females and the nest-tending male. Place the glass a slight angle, leaving about an inch or so of open space between the partition and the aquarium wall. This will afford the females some protection, but will allow them to enter the male's territory when they're ready to spawn.

Like cichlid fish, Lepomis species will readily hybridize with each other. Such ready cross-breeding is a hindrance to developing a pure strain, so breeding fish should only be kept with other sunfish of the same species. Similarly, aquarists collecting sunfish from bodies of water that contain two or more Lepomis species should examine each fish they collect to make sure it is not a hybrid.

Although Lepomis species require a large aquarium, the Enneacanthus species can be successfully bred in smaller aquariums. Found in the acid-cedar swamps of the East Coast, there are three species: the bluespotted sunfish (Enneacanthus gloriosus) the blackbanded sunfish (Enneacanthus chaetodon) and the banded sunfish (Enneacanthus obeseus).

Breeding them is a challenge of sorts, as they require soft acid water and will only eat live or frozen foods. My Enneacanthus live on a diet of live black worms, live and frozen brine shrimp, frozen blood worms, frozen glass worms and finely chopped cooked shrimp.

Like the Lepomis species, the males will defend territories and guard eggs and fry. Neither the bluespotted or blackbanded sunfish I kept excavated nests. Rather, they pushed out little hollows in the Java moss in the breeding aquariums. At spawning time, male bluespotted sunfish develop bright blue or greenish spots.

Spawning blackbandeds fade when kept over light gravels, and turn almost black when kept over dark backgrounds. The males I've kept remained in their Java moss hiding places nearly all the time, coming out only to feed or to chase intruder blackbandeds away from their territory.

For males of this species — easy pickings for larger predators — the strategy is not to conspicuously stake out a territory like the Lepomis sunfishes, but to become as inconspicuous as possible. Female blackbandeds, however, color up intensely during breeding season, with the contrast between their black and white bands increasing sharply.

Sunfish fry hatch in about four or five days. After they absorb their yolk sacs, in about a week, they will eagerly accept newly hatched brine shrimp. Brine shrimp feedings should continue for about 12 weeks. After this time, the Lepomis species can be induced to take prepared foods.

Anyone with an interest in the native fishes of North America is encouraged to join the North American Native Fishes Association (NANFA), a group fostering the conservation, preservation, collection and aquarium study of native fishes. Members receive subscriptions to American Currents, the club's journal, and the Darter, a bimonthly newsletter with fast-breaking news about NANFA and native fish. Dues are $15 per year for residents of the United States, Canada and Mexico, and $17 yearly for residents of all other countries (U.S. currency only). To join, send your name and address and a check or money order made out to NANFA to NANFA, 1107 Argonne Dr., Baltimore, MD 21218. Telephone 410-240-9050; e-mail:

Spawning Triggers
Native fish species from colder parts of the country begin spawning in the spring, when water temperatures rise, day lengths increase and insects and other food becomes more abundant. Success in spawning will probably come from replicating these conditions in the home aquarium.

Although it's probably not essential for species from warmer parts of the country, some aquarists believe native fish from colder parts of the country require a period of colder temperatures before they will spawn. I've successfully over-wintered blackbanded sunfish in a picnic cooler in my backyard. Because their temperature was low, the fish's requirements for oxygen and food were also low. Small fish, held about one to the gallon, required only about one feeding a month, and filtration was unnecessary.

Another native fish enthusiast, Peter Rollo, keeps his Enneacanthus species in fully functioning aquariums in a back yard shed. In winter, he keeps the aquariums just above freezing by surrounding them with electric heating tape.

This method allows for the use of a filter — essential, by the way, for species like darters or sculpins, which need circulating water to survive. Day lengths are also shorter in winter, so aquarium lights should be turned on for no more than eight hours a day.

It's comparatively easy to replicate the increasing day length and water temperature of spring by turning up the heater and leaving the lights on longer. It's best to do this gradually, by bumping up the heater a few degrees each day and adjusting the timer to allow for progressively more and more hours of light.

Food becomes abundant throughout the warmer months, so it's a good idea to condition the fish by feeding them larger quantities of high-quality foods. My theory is that females of some native fish species may need extra food to help them produce the large quantity of eggs they will later release.

It's best to presoak prepared foods. This way, the fish can absolutely gorge themselves without the food taking on water and rupturing their stomachs as it expands.

For Enneacanthus, live blackworms — in addition to their daily feedings of other live and frozen foods — will help to fatten them up. These species will also readily consume finely chopped earthworms or cooked shrimp.

It's important, however, not to forget about water changes. If the fish are eating more than normal, it stands to reason they'll be producing more waste. Weekly water changes of from 50 to 75 percent may be necessary.

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