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.
male peacock cichlid female peacock cichlid Example: Lake Malawi Peacock Cichlids • Peacock cichlids: sexing easy -males, bright yellows, reds and blues -females “steel” colored. • 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
Cichlid stocking techniques • Remedy: large tank, lots of hiding spaces. • A ratio of 3 females to every 1 male 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 • Discus are also mouth brooding fish. • 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
Earth eater, Satanoperca jurupari 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.
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, open-water 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