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Subject: BOUNCE nfc at actwin_com: Non-member submission from ["bockj" <bockj at erols_com>]
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From: "bockj" <bockj at erols_com>
To: <nanfa at aquaria_net>, <nfc at actwin_com>
Subject: centrarchids
Date: Thu, 6 Aug 1998 10:01:52 -0400
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Robert, thanks for sharing your article on redbelly dace with the lists.
These are really a nice fish--it's too bad the ones Cliff Zoller sent me
succumbed to that weird tail slime I had awhile. Anyway, as long as we're
sharing information, we had some questions about sunnies on the NANFA list
a week or so ago. Perhaps this article from American Currents on my
experience with sunfish will help some of the new people who are just
beginning with these marvelous creatures.
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 new
arrivals in a 65 gallon tank that I'd purchased just for the occasion.
Full
length adults, they ranged in size from six to eight inches. They held
much 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 basement
fish
room, for I forgot to tum the tank lights out. (Rest assured, the lights of
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
covers
like Siamese fighting fish. Like the hourglass on a black widow spider,
the
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
male
pumpkinseed, he was probably a hybrid between a pumpkinseed and a bluegill.
The
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
of two
or more species in the same aquarium could result in a nest full of
unwanted
hybrids.
Next, I continued my breeding attempts, this time with two types of
Enneacanthus sunfish. The males of these diminutive species were too small
to
do any damage to their tank mates, and so would not repeat the carnage of
my
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
starters,
blackbandeds and bluespots require soft acid water. This required removing
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.
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 worms,
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, 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,
coming 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 this
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
(Lepomis
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
response to
different environmental cues than did the males. My theory was that as
days
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 the
females were ready.
Tne 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
fry
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
them
heavily, once a day, on Hikari Cichlid Gold that had been soaked for an
hour 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.
I 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
fertilize 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
them 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.
NANFA member Peter Rollo has worked out a similar system, which he has
written about in earlier issues of this publication. Basically, Rollo
keeps 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 experience
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 day.
To
test whether it's really necessary to cold treat blackbanded sunfish in the
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
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 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
project, I
may try to breed redbreast sunfish (Lepomis gulosus) from the Potomac
River.
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
the
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
pectoral
fins and seem to be doing much better than my original group did. I've got
a
few wintering in a picnic cooler in my backyard, and will bring them in and
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.