fish behavior: mating strategies and reproductive patterns craig s. kasper, ph. d

Fish Behavior: Mating Strategies Fish Behavior: Mating Strategies and Reproductive Patternsand Reproductive Patterns

Craig S. Kasper, Ph. D. Craig S. Kasper, Ph. D.

IntroductionIntroduction

• We have discussed several types of common We have discussed several types of common behavior including feeding strategies, basic behavior including feeding strategies, basic behavior, and mating patterns.behavior, and mating patterns.

• Fish reproductive patterns fall into many categories Fish reproductive patterns fall into many categories spanning ovipary (egg producers), vivipary (live spanning ovipary (egg producers), vivipary (live bearers) and anthing in between (ovovivipary??). bearers) and anthing in between (ovovivipary??).

• Fish also strategize behavior to minimize parental Fish also strategize behavior to minimize parental investment.investment.

What is included in parental care?What is included in parental care?

• Construction/maintenance of nestConstruction/maintenance of nest

• Burying eggs once depositedBurying eggs once deposited

• Chasing away potential predatorsChasing away potential predators

• Fanning or splashing eggs (oxygen/cleaning)Fanning or splashing eggs (oxygen/cleaning)

• Removal of dead/diseased eggsRemoval of dead/diseased eggs

• Carrying eggs (mouth, brood pouch, head)Carrying eggs (mouth, brood pouch, head)

• Coiling around eggs to prevent desiccationCoiling around eggs to prevent desiccation

• Retreving nomads!Retreving nomads!

• Accompanying fry to forageAccompanying fry to forage

• Providing first food (mucus)Providing first food (mucus)

• Teaching feeding techniquesTeaching feeding techniques

Reproductive Pattern of Aquarium FishReproductive Pattern of Aquarium Fish

• Fish spawning patterns can be grouped according Fish spawning patterns can be grouped according to several methods. to several methods.

• We will utilize a blend of several classification We will utilize a blend of several classification schemes. schemes.

• Realize also, that most of these strategies aren’t Realize also, that most of these strategies aren’t there for the fry, but the parents!! there for the fry, but the parents!!

• Kids can be a pain sometimes!Kids can be a pain sometimes!

Reproductive GuildsReproductive Guilds

• Moyle and Cech (1988), Wootton (1990) and Balon Moyle and Cech (1988), Wootton (1990) and Balon (1975, 1981) give us a cumbersome, yet accurate (1975, 1981) give us a cumbersome, yet accurate description of description of reproductive guildsreproductive guilds in teleost fishes. in teleost fishes.

• Aquarium fish only exhibit a portion of the Aquarium fish only exhibit a portion of the reproductive strategies that exist, however we reproductive strategies that exist, however we will look at the entire list… will look at the entire list…

I. NonguardersI. NonguardersII. GuardersII. GuardersIII. BearersIII. Bearers


• Moyle and Cech (1988), Wootton (1990) and Moyle and Cech (1988), Wootton (1990) and Balon (1975, 1981) give us a cumbersome, yet Balon (1975, 1981) give us a cumbersome, yet accurate description of accurate description of reproductive guildsreproductive guilds in in teleost fishes.teleost fishes.

I. NonguardersI. Nonguarders

A. Open substrate spawnersA. Open substrate spawners

B. Brood HidersB. Brood Hiders

II. GuardersII. Guarders

III. BearersIII. Bearers




1. Pelagic spawners1. Pelagic spawners

2. Benthic spawners2. Benthic spawners

B. Brood hidersB. Brood hiders






1. Pelagic spawners1. Pelagic spawners

2. Benthic spawners2. Benthic spawners

a) Coarse-bottom spawners (rocks gravel)a) Coarse-bottom spawners (rocks gravel)

b) Plant spawnersb) Plant spawners

c) Sand spawnersc) Sand spawners

B. Brood hidersB. Brood hiders




I. NonguardersI. NonguardersA. Open substrate spawnersA. Open substrate spawners

1. Pelagic spawners1. Pelagic spawners2. Benthic spawners2. Benthic spawners

a) Coarse-bottom spawners (rocks gravel)a) Coarse-bottom spawners (rocks gravel)i. Pelagic free-embryo and larvaei. Pelagic free-embryo and larvaeii. Benthic free-embryo and larvaeii. Benthic free-embryo and larvae

b) Plant spawnersb) Plant spawnersc) Sand spawnersc) Sand spawners

B. Brood hidersB. Brood hidersII. GuardersII. GuardersIII. BearersIII. Bearers


I. NonguardersI. NonguardersA. Open substrate spawnersA. Open substrate spawners

1. Pelagic spawners1. Pelagic spawners2. Benthic spawners2. Benthic spawners

a) Coarse-bottom spawners (rocks gravel)a) Coarse-bottom spawners (rocks gravel)i. Pelagic free-embryo and larvaei. Pelagic free-embryo and larvaeii. Benthic free-embryo and larvaeii. Benthic free-embryo and larvae

b) Plant spawnersb) Plant spawnersi. Nonobligatoryi. Nonobligatoryii. Obligatoryii. Obligatory

c) Sand spawnersc) Sand spawnersB. Brood hidersB. Brood hiders

II. GuardersII. GuardersIII. BearersIII. Bearers


I. NonguardersI. NonguardersA. Open substrate spawnersA. Open substrate spawnersB. Brood hidersB. Brood hiders

1. Benthic Spawners1. Benthic Spawners2. Cave Spawners2. Cave Spawners3. Spawners on/in invertebrates (shells)3. Spawners on/in invertebrates (shells)4. Beach Spawners4. Beach Spawners5. Annual Fish5. Annual Fish

II. GuardersII. GuardersIII. BearersIII. Bearers


I. NonguardersI. NonguardersII.II. GuardersGuarders

A. Substrate choosersA. Substrate choosersB. Nest SpawnersB. Nest Spawners




A. Substrate choosersA. Substrate choosers1. Rock spawners1. Rock spawners2. Plant spawners2. Plant spawners3. Terrestrial spawners3. Terrestrial spawners4. Pelagic spawners4. Pelagic spawners

B. Nest SpawnersB. Nest SpawnersIII. BearersIII. Bearers



A. Substrate choosersA. Substrate choosersB. Nest SpawnersB. Nest Spawners

1. Rock and gravel nesters1. Rock and gravel nesters2. Sand nesters2. Sand nesters3. Plant material nesters3. Plant material nesters4. Bubble nesters4. Bubble nesters5. Hole nesteers5. Hole nesteers6. Miscellaneous material nesters6. Miscellaneous material nesters7. Anemone nesters7. Anemone nesters




A. Substrate choosersA. Substrate choosersB. Nest SpawnersB. Nest Spawners1. Rock and gravel nesters1. Rock and gravel nesters2. Sand nesters2. Sand nesters3. Plant material nesters3. Plant material nestersi. Gluemakersi. Gluemakersii. Nonglumakersii. Nonglumakers4. Bubble nesters4. Bubble nesters5. Hole nesteers5. Hole nesteers6. Miscellaneous material nesters6. Miscellaneous material nesters7. Anemone nesters7. Anemone nesters




A. External bearersA. External bearersB. Internal bearersB. Internal bearers



A. External bearersA. External bearers1. Transfer brooders1. Transfer brooders2. Forehead brooders2. Forehead brooders3. Mouth Brooders3. Mouth Brooders4. Gill chamber brooders4. Gill chamber brooders5. Skin brooders5. Skin brooders6. Pouch brooders6. Pouch brooders

B. Internal bearersB. Internal bearers



A. External bearersA. External bearersB. Internal bearersB. Internal bearers

1. Ovi-ovoviviparous1. Ovi-ovoviviparous2. Ovoviviparous2. Ovoviviparous3. Viviparous3. Viviparous

Open Substrate SpawnersOpen Substrate Spawners

• This is the most common spawning method.This is the most common spawning method.

• Example: Cichlids, Angles, Discus, Jack Dempseys, Example: Cichlids, Angles, Discus, Jack Dempseys, Oscars, Sunfish, Gobies, Damsels, ClownfishOscars, Sunfish, Gobies, Damsels, Clownfish

• Adults form permanent pair bonds. Adults form permanent pair bonds.

• The female lays the eggs on a flat surface, such as a The female lays the eggs on a flat surface, such as a rock, male fertilizes. rock, male fertilizes.

• Often aggressive protective behavior.Often aggressive protective behavior.


• A compatible pair must be found!!A compatible pair must be found!!

• This is best done by raising a group of 6-8 fry to This is best done by raising a group of 6-8 fry to maturity and picking out the pairs as they form. maturity and picking out the pairs as they form. Set them up in their own tank, condition them, Set them up in their own tank, condition them, watch & wait. watch & wait.

• If the pairs become regular egg-eaters or fry If the pairs become regular egg-eaters or fry devourers, you can remove the eggs to be devourers, you can remove the eggs to be hatched away from their parents. hatched away from their parents.


• Although not technically egg hiders, some will often bury Although not technically egg hiders, some will often bury them and move them from place to place in the tank. them and move them from place to place in the tank.

• Don't assume you lost the spawn until well past the time Don't assume you lost the spawn until well past the time when you should see them free swimming. when you should see them free swimming.

• In addition, although this group are not considered In addition, although this group are not considered Mouthbrooders some will pick the fry up in their mouths Mouthbrooders some will pick the fry up in their mouths and move them to a safer territory, especially at night and move them to a safer territory, especially at night time. Don't think they are eating the fry until many are time. Don't think they are eating the fry until many are actually missing! actually missing!

Egg HidersEgg Hiders

• Permanent pair bonds possible. Permanent pair bonds possible.

• Often female parental care. Often female parental care.

• Eggs are usually laid in a hidden area such as a cave, Eggs are usually laid in a hidden area such as a cave, flower pot or shell. flower pot or shell.

• Spawning is difficult to observed. Spawning is difficult to observed.

• Included in this group are many Dwarf cichlids, Included in this group are many Dwarf cichlids, Apistogramma, Nanacara, Namachromis,Apistogramma, Nanacara, Namachromis, Pelvicachromis, Julidochromis, Lamprologous, Loricaria, Pelvicachromis, Julidochromis, Lamprologous, Loricaria, FarlowellaFarlowella & & AncistrusAncistrus. .


• Set up a pair with several spawning choices. Set up a pair with several spawning choices.

• Feed them well and wait... Feed them well and wait...

• The female will lay the eggs within a cave or The female will lay the eggs within a cave or under a rock and the male will fertilize the eggs under a rock and the male will fertilize the eggs in unison. (Unlike, open substrate spawners, egg in unison. (Unlike, open substrate spawners, egg movement is rare.)movement is rare.)


• Absence of female from general view for extended Absence of female from general view for extended periods (2 wks) indicates spawning has occurred.periods (2 wks) indicates spawning has occurred.

• Female will be very aggressive toward male during this Female will be very aggressive toward male during this time. (May need to remove the male.)time. (May need to remove the male.)

• When the fry are free-swimming, she will bring them out When the fry are free-swimming, she will bring them out and parade them around the tank. Pay attention to and parade them around the tank. Pay attention to feeding whatever the fry require. feeding whatever the fry require.

• If male isn’t removed by now…do it.If male isn’t removed by now…do it.

• It is often good to remove the male at this point. In It is often good to remove the male at this point. In another 3-4 weeks, the female can also be removed. another 3-4 weeks, the female can also be removed.

Mouth BroodersMouth Brooders

• Set up a pair with rocks, gravel and caves. Set up a pair with rocks, gravel and caves.

• A few dither fish will help them keep their aggressions away from A few dither fish will help them keep their aggressions away from each other. each other.

• Male digs a pit in the substrate (nest). Male digs a pit in the substrate (nest).

• The female, when ripe, will begin the circular “spanning dance” The female, when ripe, will begin the circular “spanning dance” around the pit with the male. around the pit with the male.

• Eggs are laid, fertilized, then scooped up into the female's mouth. Eggs are laid, fertilized, then scooped up into the female's mouth.

• In some African Cichlids the female tries to " scoop up" the egg In some African Cichlids the female tries to " scoop up" the egg spots on the male's anal fin, thereby ensuring that the sperm has spots on the male's anal fin, thereby ensuring that the sperm has reached the eggs in her mouth (sperm drinking). reached the eggs in her mouth (sperm drinking).

Mouth BroodersMouth Brooders

• Female incubates eggs for 3 wks. Female incubates eggs for 3 wks.

• She will not eat at all in this time, unless the eggs have been lost or She will not eat at all in this time, unless the eggs have been lost or swallowed. swallowed.

• May need to move female to a second tank. May need to move female to a second tank.

• When the fry are old enough, the female will release them and guard them. When the fry are old enough, the female will release them and guard them.

• Often, she can be seen chewing up and spitting out food for them. Often, she can be seen chewing up and spitting out food for them.

• When danger approaches the fry fly at lightning speed to hide in the When danger approaches the fry fly at lightning speed to hide in the mother's mouth. mother's mouth.

• When the young have been free swimming for about three to four weeks it is When the young have been free swimming for about three to four weeks it is OK to remove the female. Cannibalism possible in active females.OK to remove the female. Cannibalism possible in active females.

Egg ScatterersEgg Scatterers

• Mostly schooling types: Barbs, Danios, Characins, Tetras & Mostly schooling types: Barbs, Danios, Characins, Tetras & Rainbows. Rainbows.

• They spawn as they school, scattering eggs all over the tank. They spawn as they school, scattering eggs all over the tank.

• Females release the eggs haphazardly; the males follow close Females release the eggs haphazardly; the males follow close behind, releasing sperm at the same time. behind, releasing sperm at the same time.

• Amazingly, the two meet and the eggs stick to whatever they land Amazingly, the two meet and the eggs stick to whatever they land on. on.

• The eggs are usually eaten as fast as they are laid by the spawners The eggs are usually eaten as fast as they are laid by the spawners and their tankmates.and their tankmates.

How do we save them??How do we save them??

Egg Scatterers: Egg Scatterers: egg salvageegg salvage

• ““Set up another tank!”Set up another tank!”

• High substrate density: plants (plastic or real) or mops. High substrate density: plants (plastic or real) or mops.

• Set up a tank with a female only.Set up a tank with a female only.

• One evening , introduce a male.One evening , introduce a male.

• The next morning they should spawn at sunrise. After a few hours, The next morning they should spawn at sunrise. After a few hours, remove the pair. remove the pair.

• Cover the tank with dark cardboard or towels. The fry will hatch in Cover the tank with dark cardboard or towels. The fry will hatch in three to four days.three to four days.

Egg ScatterersEgg Scatterers

• ““Eyelash fry” feed on infusoria (plankton), then Eyelash fry” feed on infusoria (plankton), then live baby brine shrimp, vinegar eels, live baby brine shrimp, vinegar eels, microworms, etc. microworms, etc.

• After two weeks they can take powdered flake After two weeks they can take powdered flake foods. foods.

Mop SpawnersMop Spawners

• Aphyosemion, Aplocheilus, Epiplatys, Rivukus, Aphyosemion, Aplocheilus, Epiplatys, Rivukus, SimposonichthysSimposonichthys

• Lay their eggs in mops or in plants. Lay their eggs in mops or in plants.

• What makes these fish different from the egg lay What makes these fish different from the egg lay scatterers is that their eggs are harder and scatterers is that their eggs are harder and larger, and they only lay about 20 -30 a day. larger, and they only lay about 20 -30 a day.

Mop Spawners: Tank SetupMop Spawners: Tank Setup

• Hang several mops, add a sponge filter and a Hang several mops, add a sponge filter and a heater if needed. Add a pair of fish. heater if needed. Add a pair of fish.

• Female will lay the eggs deep in the mop or the Female will lay the eggs deep in the mop or the plant, male fertilizes them. plant, male fertilizes them.

• You must pick the eggs out of the mop daily and You must pick the eggs out of the mop daily and put them in a small container with anti-fungal put them in a small container with anti-fungal medication added (methylene blue or acriflavin). medication added (methylene blue or acriflavin).

Mop Spawners: fryMop Spawners: fry

• Store the eggs in a darker place, at the required temp. Store the eggs in a darker place, at the required temp. (varys between spp.) (varys between spp.)

• Incubate 2-3 wks for killies, 7-10 days for rainbows. Incubate 2-3 wks for killies, 7-10 days for rainbows.

• Fry can be removed with an eyedropper or pipette to Fry can be removed with an eyedropper or pipette to another small container or tank with the correct water another small container or tank with the correct water parameters and some Java moss or similar floating parameters and some Java moss or similar floating plants. plants.

• Fry can be fed live food right away. Fry can be fed live food right away.

Odd fish out…Odd fish out…

• Brood parasitism? Benefit or cost?Brood parasitism? Benefit or cost?

fish behavior: mating strategies and reproductive patterns craig s. kasper, ph. d

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