[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Nice article on Green Sunfishhhhhhhhhhhhh


  THE GREEN SUNFISH (Lepomis cyanellus)
  By Peter R. Rollo,
prollo at juno_com
In  Southeastern Pennsylvania, spawning begins in early
June  or when  the  water temperature approaches 70 F.  In
the  summer  of 1992, while  on  a  fishing  trip in mid
June, I was  able  to  observe Bluegill,  Pumpkinseed,  and
Redbreast Sunfish  performing  their spawning  ritual.   The
spawning species were  verified  when  I caught  a few of
the fish on my fishing rod.  I was not  able  to observe
the  nest  building process, as the  males  had  already
completed  this  task  and were guarding  their  nests  from
all intruders.   The  nests were constructed in water  less
than  12 inches  deep  and closely spaced (the edge of the
nests  touching adjacent  nests).  In the spawning ritual,
females  approach  the males  and  begin  circling each
other with fins fully  extended.  After  a short time the
pair stops circling and the female  tilts her   body   to
a  45   angle.   The  eggs  are  released   and
simultaneously fertilized by the male.  The females rarely
spawn with  only  one male.  They generally move on to other
males  to complete spawning while the males remain on their
nests to  guard the eggs.
Throughout  the summer of 1992 I collected several green
sunfish for  my aquarium.  Some had to be returned to their
original body of  water due to conflicts with the other
sunfish already in  the tank.   Eventually I was able to
collect two individuals  of  the same size that got along
with minimal fighting.  A third juvenile green sunfish and
brown bullhead catfish, about the same size  of the
others,  found  in  a  local  pet  shop  were  also  added.
Amazingly, all four fish got along.  Being juveniles I had
no way of accurately sexing the sunfish, but I hoped that I
had captured a pair.  In Pennsylvania, my understanding is
that Sunfish can be legally  collected with a fishing rod
and valid fishing  license.  Instead  of  taking  them home
to fillet, they  accidently  found their  way  into  my
aquarium.  As long as the fish  are  cleanly hooked  in the
mouth, they suffer no ill effects and are  feeding by the
first or second day.
I maintained the fish all summer in a "community" style 20
gallon high  aquarium in my outdoor shed.  The shed is
equipped  with  a thermostatically controlled exhaust fan to
prevent heat buildups.
The average summer temperature of the aquarium water was
about 80
F  with  a pH of 7.0.  No other attempts to alter water
chemistry were  made.  Filtration was provided by a Fluval 3
internal power filter connected to a spray bar and a Penn-
Plax Clear-Free corner filter  (Model  CF-1).  Drift wood,
small  rocks,  a  flower  pot turned  on  its side and about
an inch and a half of gravel  were provided  along  with
the aquatic plants Vallisneria,  Ludwigia, Sagittaria,
Bacopa and Elodea (Anacharis). Anacharis  grows  wild in
the  waters  where  I  caught the  sunfish.   The  plants
do moderately well in the summer, but really thrive and grow
quickly in  the winter when the water temperature is below
50 F. The tank is  enclosed  in a plywood box with removable
lid insulated  with styrofoam. An air space of about 4
inches surrounds the sides and top  of  the tank.  Minimal
heating is provided using  a  voltage regulator connected to
heat tape.  The heat given off by the heat tape  warms the
air space.  This warm air is pumped into the tank by  the
air pump and effectively prevents freezing or major drops in
temperature.  The heat is manually controlled and  used
only when excessively cold.
In  the  summer the sunfish are fed moderately heavy every
second or third day and in the winter they are fed sparingly
every three or  four  days whenever the water temperature
rises above  50  F.  Below 50 F the food in their stomachs
digests so slowing that  it can  actually  spoil  before
digestion is complete,  killing  the fish.    Besides,   I
am  trying  to  recreate   their   natural environment, and
minimal feedings in the winter is  part  of  it.
The  foods offered include fresh frozen mummichogs, grass
and  Atlantic silversides, grasshoppers, crickets,
chicken  heart, freeze dried krill, freeze dried daphnia,
dried  shrimp,  dry cichlid pellets and any other  insect  I
catch. The Mummichogs, grass shrimp and Atlantic silversides
caught with a minnow trap and net while vacationing at the
beach.  These  foods  are their staple winter diet when the
regular  live foods are not available.

There  are  no provisions to chill the water in the summer.
The fish endure  an  average summer temperature of 80  F
and  an  average winter  temperature of about 40 F.  Forty
percent  water  changes are   generally  made  once a week
in the  spring  and  fall  but usually every few days in the
summer.  Twenty-five percent  water changes  are  made about
once a month in the winter  (when  water temperatures  are
consistently below 55 F). Don't  be  lax  with water
changes.  These fish have big appetites and produce  large
amounts of waste. It is extremely important that all water
added to  the aquarium during water changes be the same
temperature  as the  water in the aquarium or temperature
shock to the fish  will result.
This group of fish were overwintered as naturally as
possible  in the hope that they will be properly cold
conditioned and ready to spawn  in  the  spring.   As soon
as the weather  began  to  warm another  20  gallon high
spawning tank was set up  in  the  shed.  Except  for the
gravel and sponge filter the tank was kept  bare.  A
chiller  unit was utilized to maintain an optimum
temperature (70 F) for spawning and raising fry during the
hot summer months.  In  April, 1993 as the water temperature
slowly increased two  of the  sunfish  began to swell with
eggs but the remaining  sunfish did not exhibit any male
behavior or female egg development.   By the  end  of  June,
1993 nothing had changed and  I  decided  to release  that
fish to its native waters and attempt  to  capture another
fish in the hope I could find a male.  Fishing was  poor the
day  I  went out and was only able to catch one  beautifully
colored  juvenile  green  sunfish.   I  was  hoping  its
bright coloration meant it was a male because none of the
other  fish  I captured  showed such color.  As the fish
matured (he  more  than doubled  his size in three months) I
realized it was a  male  and hoped it could be induced to
build a nest and spawn.
October  approached  and by this time I was  becoming
frustrated because I had already put a year and a half of
effort and alot of money  into  this experiment and did not
want to wait  till  next spring  to  see if spawning would
occur.  November began  and  no interest  to  spawn  was
shown by the fish.   The  beginning  of November  was
warmer  than normal and  the  temperature  in  the community
sunfish tank spiked about 8 F in a short time  period.
The  male  sunfish began excavating gravel in all  areas  of
community  tank.   When  male sunfish are ready  to  spawn
colors intensify, they excavate a nest in the gravel and
await  a
receptive  female.  Even though the male sunfish appeared
to  be
excavating  a  nest  and I noted his colors  were  brighter
normal I paid no attention to what he was up to.  On
November 15,
1993  I  checked on them at 10 PM and every thing  seemed
as  it
should.   However, when I went out to check on them at 10
AM  on
November 16, the male was stationed in the middle of the
nest and had  all the other fish pinned in the opposite
corner of the tank and  would not let any of them out.  I
thought this odd  behavior but  I still had not realized
what had occurred.  I looked at the larger  female who the
night before was loaded with eggs and  saw that  she was as
thin as a rail.  When I quickly looked  back  at the male I
noticed eggs, hundreds of eggs.  They had spawned over night
and the male was protecting the eggs.  The fertilized  eggs
are  adhesive, perfectly round, colorless and approximately
1/16 of an inch in diameter.
I  quickly removed all the fish except the male and put
them  in
the  spawning  tank.  The spawning female was a bit  ragged
torn  fins and the other fish were all in good shape.  The
filter and spray bar were removed and replaced with an air
sponge  filter to ensure that none of the eggs or  fry
would  be
sucked  into  the filter.  Air flow was high enough  to
cause  a
light  current in the aquarium.  The current prevents any
material  from settling on the eggs and wigglers.   A  25%
change  was  also made.  The community tank was not intended
spawning and was in need of a change anyway.
On November 17 I noticed that any eggs kicked up by the male
quickly  eaten  so I took him out and put him in with  the
other fish.   I  now  anxiously  waited for  the  eggs  to
hatch.   No chemicals  were added for egg protection.
Clean,  well  filtered and  aerated  water is sufficient.
Based on my  reference  books sunfish  eggs  hatch in 3-5
days at 80 F and  quicker  at  cooler temperatures.  On
November 19 the eggs finally hatched.  It  only took  3
days  at a water temperature of 65 F and a  pH  of  7.0.
There   were  no  apparent  problems  with  bacterial  or
infestations  of the eggs as evidenced the large number  of
that hatched.  With a little care and the heat tape turned
way up
I was able to maintain the tank to within plus or minus 2 F
of 65
F  to ensure proper incubation of the eggs and development
of the
wigglers into fry.  The wigglers were entirely clear, no
markings could be seen.  Within 24 hours (November 20) eye
became apparent and the wigglers started to take the form of
fish 24  hours  after  that  (November 21).   Fifteen  to
twenty-five percent water changes are made every day and so
far all is well.
With  regard to how long it takes for the wigglers to become
swimming my references estimate about one week.  On November
25 I
noticed  a  few  fry making their first attempts at
swimming  on their  own.  I offered a very small quantity of
brine shrimp  but none  were  accepted.  No further
offerings were made  until  the 27th.   This  was the eighth
day since hatching and  dozens  were free  swimming.  I
again offered a very small quantity  of  brine shrimp  and
for  the first time the fry began feeding.   By  the ninth
day all were free swimming and brine shrimp feedings began
twice  a  day, once in the morning and once in the evening.
The feedings require that the aeration and filtration be
turned  down to  a  minimum.  This prevents the shrimp from
being sucked  into the   filtration  system  and  because
the  fry   are   somewhat uncoordinated they cannot
successfully capture the moving  shrimp in moving water.
With still water it takes them several attempts before  they
can capture the shrimp.  This will quickly  pass  as the
fish  grow and become proficient swimmers.  It  is  easy  to
determine  which fry are feeding.  Since their bodies  are
still transparent, consumed shrimp give the fry orange
Two  months have passed and the majority of the fry are  now
 inch  or  larger.   The remaining fry number  about  one
to  two hundred.   The fry that were unable to swim properly
and/or  feed consistently  quickly  died.  At first  several
fry  were  dying daily,  but now virtually none are dying on
a regular  basis.   I figured  I  lost  about  100  fry to
what  I  will  call  natural selection.  At any rate, their
survival is by far better than  it would  be in their
natural habitat.  Due to limited space,  I  am experiencing
cannibalism of the smaller fry by  the  larger  fry because
I  am unable to provide the tanks necessary to  separate out
the larger fry as needed.  The fry are still mostly
dependent on  brine  shrimp, but will be weaned off the
shrimp as  soon  as they are large enough and can be
persuaded to accept other foods.  Even after two months most
of the fry still do not resemble their parents,  i.e. their
pelvic fins are not yet visible (dorsal  and anal  fins  are
faintly  visible) and  their  bodies  are  still
substantially  transparent.  I will consider them juveniles
when their body shape and coloration resembles adult
sunfish.  This is expected to occur in the next one to two
months.  This experience has  been  very rewarding and
helpful in understanding  the  life cycle of the Green
Sunfish as well as Sunfish in general.  I look forward  to
spring when I hope to experience another spawning  of the
Green Sunfish.

Robert Rice
Help Preserve our Aquatic Heritage join the NFC
email us at NFC at actwin_com
website  http:\\nativefish.interspeed.net\

You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com
Or call Juno at (800) 654-JUNO [654-5866]