Transcript Mouth Brooding Fish: with an emphasis on cichlids Dr. Craig Kasper HCC Aquaculture Program.

Mouth Brooding Fish:
with an emphasis on cichlids
Dr. Craig Kasper
HCC Aquaculture Program
Introduction
• Mouth brooders--fish that hold their eggs in their mouth until
their young are free-swimming.
• Main advantage: larger, self sufficient young.
• Reproductive strategy: common in cichlids
• Sexing: Difficult. Methods vary greatly.
Example: Lake Malawi Peacock Cichlids
• Peacock cichlids: sexing easy
-males, bright yellows, reds and blues
-females “steel” colored.
male peacock cichlid
female peacock cichlid
• Other methods: Dorsal fin morphology.
Males typically pointed while females,
rounded.
Mouth Brooders
• Melanochromis spp. are easy if
properly fed and conditioned.
Note: Male is literally the opposite
of the female in this photo.
• Some species of cichlids fight…a lot!!
• How do we fix it?
Melanochromis auratus
• Remedy: large tank, lots of hiding spaces.
• A ratio ofCichlid
3 females tostocking
every 1 maletechniques
doesn’t hurt either.
-however, even with a 1:1 ratio, they will still spawn.
More…
• When breeding mouth-brooders, it is important to keep a
careful watch over your fish.
• When a fish spits its fry, they fry will most likely be
ravenously consumed by the fish in the tank.
• To avoid this, you can "spit,” or “milk" their females before
they release the fry.
• This should be done with great care so as to not injure the fish.
Discus
• Some discus are also mouth brooding fish, however
this is very rare to observe, particularly in captivity.
• They are also difficult to sex. It may be best to “let them sort it out.”
• A density of breeding adults (5-6) is a good starting point if you aren’t sure
(and you most likely won’t be.)
• Discus eggs need soft water and low pH to hatch.
• Be sure to provide sufficient substrate for the fish as well.
• Fry hatch in 50-60hrs!! Fry will also feed off the parental slime coat for
the first time. Later they can be weaned onto live or dry diets.
Discus
• Expect 50-70 fry per batch when rearing discus.
• Transfer of fry from spawning tank to growout must be
done carefully as the fry tend to be very temperature
sensative!
Jawfish Opistognathus spp.
• Jawfish, a marine spp. also engage in mouth-brooding.
• Jawfish exhibit interesting nesting behavior.
• Spend most of the day “cleaning house.”
• Territorial defense is
offen aggressive.
Marine Mouthbrooders
• Captive breeding possible, but difficult.
• Paternal egg care.
• Fry hatch in 7 days.
• Fry need there own space.
• Larval fish need clean water and rotifers
• Once large enough brine shrimp are used.
• Tank Conditions: 72-82°F; sg 1.021-1.023; dKH 8-12
Mouth Brooding: Part 2
Mating strategies, family units and brood care
Still more mouth brooding fish facts…
• We began discussing mouth brooders last time and observed
some cool examples.
• But are all mouth brooding fish the same? Not entirely!
• Like most other fish we’ve observed, classification seems to
be the rule, or curse.
• Two groups of mouth brooding fish classification exists. Its
based on the stage of development when the fish occupy the
mouth cavity of the parent.
Egg or Larval
• Mouth brooders can be broken up into ovophiles and
larvophiles.
• Ovophile, or egg-loving mouth-brooders, lay their eggs in a
pit, which are sucked up into the mouth of the female.
• The small number of large eggs hatch in the mother’s mouth,
and the fry remain there for a period of time.
Egg or Larval
• Fertilization often occurs with the help of egg-spots, dummy
eggs, egg dummies, or false egg spots, which are colorful
spots on the anal fin of the male.
• When the female sees these spots, she tries to “pick up” the
egg-spots (eggs), but instead gets a mouthful of sperm
fertilizing the eggs in her mouth!
• Examples of Ovophile mouthbrooders
include; Aulonocara, Haplochromis,
and Pseudotropheus as well as several
species of Thai Bettas.
Haplochromis spp., Rock Krib
Mouth Brooding Bettas
• Unlike their bubble-nesting cousins, mouth brooding bettas
evolved in an environment which wasn’t favorable to bubble
nests (moving water).
• They require slightly acidic pH and warm temps.
• Rem: Female bettas tend to have a
smaller head and build, drab
coloration, and short fins.
Betta pugnax
Larva-loving mouthbrooders
• Larvophile, or larvae-loving mouth-brooders, lay their eggs on a substrate
and guard them until the eggs hatch. This is also known as delayed mouth
brooding.
• After hatching, the female picks up the fry and
keeps them in her mouth.
• When the fry can fend for themselves,
they are released.
• Examples of Larvophile mouth-brooders are
Geophagus (eartheaters) and Sarotherodon
(tilapia) spp.
• Some eartheaters “in between” behaviors.
Earth eater, Satanoperca jurupari
Brood Care
Brood Care
• Cichlids take care of their young in six different ways.
• Nuclear or Parental Family: Both parents care for young.
• Nuclear families are usually formed by monogamous, openwater brooders, although exceptions are common
(Pterophyllum [angelfish], Symphysodon [discus], Cichlasoma
[convicts!])
• It is generally very difficult to
distinguish between the sexes.
Why might this be so??
Paring Strategies: Brood Care
• Matriarch/Patriarch Family: The female watches over the
brood, while the male defends the territory.
• When the fry become free-swimming, the parents bear the
tasks of parenthood equally.
• This family form is usually
formed by monogamous,
open-water brooders.
• Sexual dimorphism and
dichromatism is common.
Cichlasoma regani
Paring Strategies: Brood Care
• Patriarch/Matriarch or Male-with-Harem Family: The
male defends a large territory, which includes multiple
spawning sites of several females.
• Each female assumes the responsibility of her own brood.
• The male is polygamous, and clear sexual dimorphism is
present.
• This form takes place among cavity
brooders Apistogramma, Julidochromis,
Neolamprologus, and Pelvicachromis .
Apistogramma cacatuoides
Paring Strategies: Brood Care
• Matriarch Family: No bond is formed between the pair.
• The female cares and guards the eggs and the fry.
• In this family pattern, the fish are agamous, and usually the
female is an ovophile mouthbrooder Aulonocara,
Haplochromis, and
Pseudotropheus.
Aulonocara baenschi,
Rubin Red Peacock Cichlid
Paring Strategies: Brood Care
• Patriarch Family: As with the Matriarch Family, no bond is
formed between the parents.
• The male carries the eggs and the fry.
• No sexual dimorphism or dichromatism can be found.
• Only one mouthbrooder forms
a true patriarch family,
Sarotherodon melanotherow,
the Blackchin tilapia
Sarotherodon melanotherow, Blackchin tilapia
Paring Strategies: Brood Care
• Extended Family: The parents as well as the offspring of
previous spawning care for the young.
• Extended Families are formed by cavity brooders of Lake
Tanganyika, including the fish belonging to the genera
Julidochromis and Neolamprologus.
Julidochromis ragani, striped Julie
Neolamprologus brichardi
• http://video.nationalgeographic.com/video/player/animals/fishanimals/spiny-rayed-fish/cichlid_movingyoung.html