Re: NANFA-- Bluegills

Bob Bock (
Tue, 17 Jun 2003 21:10:57 -0400

----- Original Message -----
From: "Bob Bock" <>
To: <>
Sent: Tuesday, June 17, 2003 9:02 PM
Subject: Re: NANFA-- Bluegills

> Also, space. Spawning males get nasty and are likely to kill tankmates.
> Copied below is an article I wrote on sunfish for American Currents a few
years ago.
> Hope it's useful.
> Bob
> Centrarchid Observations
> I began my centrarchid observations about three years ago, when I
> brought back three pumpkinseed sunfish (Lepomis gibbosus) from a fishing
> trip.
> I'd been enchanted by this colorful species ever since I was 10 years old,
> when
> I caught pumpkinseeds with tiny hooks and a bobber fished from a hand held
> line.
> Observing the spawning and nest-tending behavior of this species would
> be an interesting experience, I thought at the time. I set up my three
> arrivals in a 65 gallon tank that I'd purchased just for the occasion.
> length adults, they ranged in size from six to eight inches. They held
> of
> their color in the aquarium--neon blue cheek lines, bright yellow-orange
> bellies
> and blue trim around the dorsal and tail fins. All of them acclimated to
> tank
> life remarkably fast. Within 24 hours, they were schooling against the
> glass
> and chas-ing their reflections. They even took meal worms from my hand.
> This peaceful scene soon ended, however, as I wit-nessed the behavioral
> changes male centrarchids undergo in response to extended day length and
> warm
> tempera-tures. I must've been preoccupied that night as I left my
> fish
> room, for I forgot to tum the tank lights out. (Rest assured, the lights
> all
> my native tanks are now connected to timers.) The next day, the once
> peace-ful
> male had metamorphosed into a ferocious monster. He hovered over the
> spawning
> pit he had just excavated in the gravel, as the females cowered behind the
> rocks. I removed the battered females and treated them faithfully with
> antimicrobials I bought from the aquarium store. Despite my best efforts,
> they
> eventually died of infec-tion from their wounds.
> The male remained in spawning mode, continuing to enlarge the nest by
> "shimmying" like a mollie, blasting the gravel out of his way with the
> back-and
> forth motion of his tail.
> Although the breeding attempt failed, I did learn from it-something that
> had never been described in any of the references I'd collected. 'Me
> conspicuous opercular spot-the bright red "ear" spot on the edge of the
> fish's
> gill covers-served a highly useful purpose. When I introduced another
> pumpkinseed to the tank (separating the new arrival from the original male
> with
> a glass partition) the two fish charged the glass, flaring their gill
> like Siamese fighting fish. Like the hourglass on a black widow spider,
> opercular spot was red, nature's universal warning color. Its meaning to
> rival
> males is unmistakably clear: stay away.
> I also learned that many Lepomis species will hybridize readily with
> related species. The new fish, stouter bodied and more drab than my
> original
> male, was not a female, as I had thought. Less colorful than a nesting
> pumpkinseed, he was probably a hybrid between a pumpkinseed and a
> 'Me
> latter form is a favorite of fishermen and has been extensively stocked
> throughout the U.S.
> Such ready crossbreeding is a hindrance to devel-oping a pure strain.
> Aquarists collecting sunfish from bodies of water where there are two or
> more
> species present should examine each individual closely to make sure it is
> not a
> cross between different species. Further-more, housing males and females
> two
> or more species in the same aquarium could result in a nest full of
> hybrids.
> Spring 1997 American Currents 20
> Next, I continued my breeding attempts, this time with two types of
> Enneacanthus sunfish. The males of these diminutive species were too
> to
> do any damage to their tank mates, and so would not repeat the carnage of
> earlier experiment with pumpkinseeds. I obtained several bluespotted
> sunfish
> (Enneacanthus gloriosus) and a few blackbanded sunfish (E chaetodon).
> Although
> I kept them for more than two years, they've yet to spawn. From the
> beginning,
> I was meticulous about providing them everything they needed. For
> blackbandeds and bluespots require soft acid water. This required
> the
> dissolved limestone from my local tap water by running it through either a
> deionizer or a water softening pillow. I then acidified the water, by
> filtering
> it through peat moss and adding commercial pH reducing solutions. I
> performed
> this water softening ritual once a week, when I did 20 percent water
> changes.
> Pumpkinseed. Illustration by Robert Bock.
> Too fussy to accept dried or prepared foods, my Enneacanthus lived on a
> diet of live black worms, live and frozen brine shrimp, frozen blood
> frozen glass worms, and finely chopped cooked shrimp.
> Although my Enneacanthus never spawned, I learned something from that
> experience as well. Again. I observed first hand what I'd never seen
> written
> in any text book. Most male centrarchids become conspicuous at spawning
> time.
> Their colors intensify and they stake out territories clear of any cover.
> Presumably, this increases the chances that they will be seen by breeding
> females, and allows rival males to give them a wide berth. My male
> pumpkinseed,
> for example, not only excavated a nest in the open, he uprooted all the
> plants
> near the nest.
> Contrary to what some of the written accounts say, my male blackbanded
> sunfish did not excavate spawning pits in the gravel as the larger Lepomis
> species do,
> 21 American Currents Spring 1997
> although they did stake out a small territory of sorts. In fact, they
> became as inconspicuous as possible. They pushed out hollows in the Java
> moss I
> had planted and remained in these hiding places almost all the time,
> out
> only to feed or to chase intruder blackband-eds away from their territory.
> During breeding season, male blackbandeds also change color slightly, to
> match their surroundings. Those kept against dark gravel will turn dark,
> whereas those kept on light colored gravel tend to fade. For males of
> species-bereft of any defenses against predators-the reproductive strategy
> was
> not to con-spicuously stake out a territory, but to become as difficult to
> see
> as possible.
> In contrast to the larger Lepomis species, the female blackbanded
> sunfish became more intensely col-ored during breeding season, with the
> contrast
> between their black and white bands increasing sharply. To my
> consternation,
> the female blackbanded sunfish I kept never ripened.
> After three years of perseverance, I was finally rewarded with a
> spawning by another species. I had col-lected five longear sunfish
> megalotis) on hook and line from a stretch of the C&O Canal, outside
> Washington,
> D.C. This species is native to the Midwest, but was somehow introduced to
> the
> area.
> I had set them up in a 65 gallon tank, along with juveniles of other
> sunfish species I had brought home from various fishing and collecting
> trips.
> At some point, it occurred to me that female sunfish might spawn in
> to
> different environmental cues than did the males. My theory was that as
> grew longer in the first cool days of spring, the males would enter the
> shallows
> and prepare their nest sites, getting things in order for the time when
> females were ready.
> 'ne females, on the other hand, might not respond so much to day length
> as to temperature. As tempera-tures rose, the populations of aquatic
> insects
> and crus-taceans would also increase, and the females would be assured of
> extra
> food for egg development. Warmer temperatures would also ensure greater
> survival.
> After the male longears had staked out their ter-ritories, I added a
> heater to the tank and brought the water temperature up to 77'F. I fed
> heavily, once a day, on Hikari Cichlid Gold that had been soaked for an
> or
> so beforehand. To compensate for the large
> quantities of waste these fish generated, I performed large scale water
> changes-sometimes as much as 75 percent each week.
> Within about two weeks, one of the males had excavated the typical
> circular centrarchid nest in the gravel. The night he completed it, I
> noticed a
> female approaching the nest for a brief instant before being chased away.
> set
> my camcorder up in front of the tank. For about 20 minutes, the female
> approached repeatedly, and was chased away each time.
> As the male left the nest to chase both the female and the various other
> sunfish species I kept in the 65 gallon tank, other longear males entered
> the
> nest briefly before being chased by the dominant male. Presumably, these
> were
> "sneakers," lower ranking males attempting to sneak in and quickly
> the
> eggs before the dominant male could notice them.
> At this point, I divided the tank with a glass parti-tion, to separate
> the spawning pair from the other fish, which the male was compelled to
> chase.
> Freed from the distraction, the pair soon began spawning. The female swam
> at
> about a 45' angle, while the male swam upright, their ventral fins nearly
> touching. The pair circled the nest for about 30 minutes as the female
> slowly
> released her eggs and the male fertilized them.
> The male fanned the eggs until they hatched about five days later.
> Unlike the reports I've read of other Lepomis species, he did not tend the
> fry
> carefully until they were free swimming, but seemed to lose interest in
> at
> this point. When the small Texas cichlid I'd kept in the tank began
> nonchalantly picking them off, I removed all of the adult fish.
> Initially, the fry were tiny and helpless-nearly impossible to see with
> the naked eye. The only detail I could distinguish were the thread-like
> tails
> above the yolk sack. The fry needed no food for about a week, after which
> time
> they readily consumed brine shrimp nauplii. After 12 weeks, the fry
> eventually
> began to accept finely crushed bits of Hikari Cichlid Gold,
> Cold treatment
> Sunfish spawn in the spring, presumably in response to warmer
> temperatures and longer day lengths. Many references state that sunfish
> need
> colder tempera-tures in order to spawn. To cold treat my blackbanded
> sunfish, I keep them in an old picnic cooler in my backyard for a month or
> two.
> Because the fish's tem-perature is kept low, they need little food and
> oxygen.
> Because they only eat about once a moth, aeration and filtration is
> unnecessary.
> Blackbanded sunfish. Illustration by Robert Bock.
> NANFA member Peter Rollo has worked out a similar system, which he has
> written about in earlier issues of this publication. Basically, Rollo
> his
> tanks from freezing by surrounding them with an elec-tric heating tape.
> This
> method permits the use of a filter, something my picnic cooler cold
> treatment
> doesn't allow for.
> Rollo and I disagree on the role that day length plays in sunfish
> spawning. Rollo contends that day lengths are irrelevant, that the shift
> from
> cold tempera-ture to warm is the sole spawning trigger. From my
> with
> the larger pumpkinseeds and longears, however, I believe that longer day
> lengths
> are influential in triggering the nest-building urge in males. For this
> reason,
> I winter my centrarchids with a maximum of only eight hours of light a
> To
> test whether it's really necessary to cold treat blackbanded sunfish in
> winter, Joe Hanyok has taken a few that I brought back from the New Jersey
> Pine
> Barrens and overwintered them at the same temperature he keeps his house.
> If
> they spawn, he's promised to let me know.
> In springtime, food also becomes more abundant. My theory is that
> female sunfish need extra food to help them produce the large quantity of
> eggs
> they will later release.
> For the longear sunfish I spawned, I was able to fatten them up with
> daily feedings of Hikari Cichlid Gold. I've found that it's best to
> pre-soak
> prepared foods. This way, the fish can absolutely gorge them-selves
> 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
> also greedily consume finely chopped earthworms or shrimp.
> Keeping sunfish has provided me with a unique opportunity to observe
> fascinating behaviors that few people have ever seen. For a future
> I
> may try to breed redbreast sunfish (Lepomis gulosus) from the Potomac
> This species is not as colorful as many of the other Lepomis species, but
> what
> color they do have-the bright orange breast-they tend to hold better in an
> aquarium than do other Lepomis species.
> On my last trip to the New Jersey Pine Barrens with Peter Rollo, I
> brought back two mud sunfish (Acantharcus pomotis). These are highly
> efficient
> ambush predators. It's a mystery why there seem to be so few of them in
> wild. I think I'll turn up the temperature on them, to see if there is
> anything
> in their spawning or fry rearing habits that account for their sparse
> numbers.
> I also brought back several blackbanded sunfish and a, few banded
> sunfish (Enneacanthus obesus) from my Pine Barrens trip. These seem to be
> doing
> better than the original group I brought back from Delaware. This time,
> instead
> of softening and acidifying my tap water, I've been collecting rain water
> from
> my roof. (Before using this for water changes, I run it through a water
> softening pillow to remove any heavy metals that may be in it.) More than
> eight
> months later, the blackband-eds still have the orange trim in their
> fins and seem to be doing much better than my original group did. I've
> a
> few wintering in a picnic cooler in my backyard, and will bring them in
> try
> to spawn them in a few weeks.
> But whether or not I'm successful in getting these four species to
> spawn, I'll no doubt learn more from other sunfish species in the future.
> The sheer diversity of this family of fishes will no doubt provide me
> with fascinating observations for years to come.
> :
> ----- Original Message -----
> From: "Nick Zarlinga" <>
> To: <>
> Sent: Tuesday, June 17, 2003 12:48 PM
> Subject: RE: NANFA-- Bluegills
> > >What are their requirements?
> >
> > water, maybe some food............that's about it
> >
> > Nick Zarlinga
> > Aquarium Biologist
> > Cleveland Metroparks Zoo
> > 216.661.6500 ext 4485
> >
> >
> > -----Original Message-----
> > From: On Behalf
> > Of
> > Sent: Tuesday, June 17, 2003 9:47 AM
> > To:
> > Subject: NANFA-- Bluegills
> >
> >
> > Does anyone keep bluegills? What are their requirements?
> > --
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> > /"Unless stated otherwise, comments made on this list do not necessarily
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> > / Association"
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/"Unless stated otherwise, comments made on this list do not necessarily
/ reflect the beliefs or goals of the North American Native Fishes
/ Association"
/ This is the discussion list of the North American Native Fishes Association
/ To subscribe, unsubscribe, or get help, send the word
/ subscribe, unsubscribe, or help in the body (not subject) of an email to
/ For a digest version, send the command to
/ instead.
/ For more information about NANFA, visit our web page,