FISH

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FISH

• FISH BIOLOGY AND HUSBANDRY

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TaxonomyTeleosts bony fish

• soft rayed teleosts

• spiney rayed teleosts

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BIOLOGY
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Fins

• supported by rays
• two types of rays
• soft
• spines

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Fin Identification

• unpaired fins
• dorsal
• caudal
• anal
• paired fins
• pectoral
• pelvic

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Skin

• epidermis
• mucous glands
• alarm cells
• cuticle
• dermis
• scales
• hypodermis

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Scales

• placoid
• ganoid
• cycloid
• ctenoid
• absent

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Lateral line

• sensory system
• a line of pores lead to mechanoreceptors
• environmental information
• pressure, currents, sound

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Color

• cells
• chromatophores
• pigments
• iridophores
• reflective substances
• control
• endocrine system
• nervous system

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Anatomy overview
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Respiratory system

• lungs
• gills
• bilateral
• operculum

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Gill structure

• gill arches
• primary lamellae (filaments)
• secondary lamellae

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Cardiovascular system

• 2 chamber heart
• atrium
• ventricle
• sinus venosus
• bulbus arteriosus

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Circulation

• venous blood to heart
• hepatic portal system
• renal portal system
• heart to gills
• via ventral aorta
• gills to body
• via dorsal aorta

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Red blood cells

• elliptical and nucleated
• no bone marrow
• main source
• head kidney

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White blood cells

• Similar to mammalian
• no lymph nodes or GALT
• lymphocytes gt neutrophils
• lymphoid tissues
• thymus
• head kidney
• spleen
• melanomacrophage centers

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Excretory system

• gills
• kidneys
• anterior kidney
• posterior kidney

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Osmoregulation

• electrolyte balance
• freshwater vs saltwater

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Osmoregulation

• freshwater fish
• water diffuses in
• ions diffuse out
• drink little
• lots of dilute urine
• actively reabsorb ions
• kidneys
• gills

• saltwater fish
• water diffuses out
• ions diffuse in
• drink a lot
• concentrated urine
• actively excrete ions
• kidneys
• gills
• gut

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Swim bladder

• Two types
• physoclistic
• capillary network
• physostomatous
• pneumatic duct
• functions
• buoyancy
• sound, pressure detection

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Digestive system

• Stomach
• intestine
• pyloric
• middle
• rectal
• spiral colon
• pyloric cecae
• liver
• pancreas

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Nutrition

• Species variation
• food
• feeding behavior
• time
• location
• obtaining food
• general fish nutrition
• protein and lipids gt carbohydrates

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Neuroendocrine system

• brain
• forebrain
• olfactory bulbs
• midbrain
• optic lobes
• cerebellum
• spinal cord

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Electrical system

• electric organs
• electroreceptors
• examples
• electric eel
• electric catfish
• electric ray

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Biolumination

• self -luminous
• photophores
• luciferase
• symbiotic bacteria

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• WATER QUALITY

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Water environments

• freshwater
• brackish water
• saltwater

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• Freshwater system
• specific gravity 1.00
• Brackish system
• specific gravity 1.01

• Saltwater system
• specific gravity 1.02

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Bioload

• Nonaerated freshwater
• 1 inch fish/ gallon
• aerated freshwater
• 3 inches fish/ gallon
• saltwater
• 0.5 inches fish/ gallon
• excluding tail fin

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Ammonia

• Nitrogenous
• fish waste product
• toxic

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Nitrification

• Bacteria Bacteria
• (Nitrosomas) (Nitrobacter)
• ammonia nitrite
  nitrate
  

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Conditioning a new tank

• seeding bacteria
• limited population
• time

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PH

• ranges
• freshwater 7.0-7.6
• brackish 7.0-7.6
• saltwater 8.1-8.3

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Decreased PH

• effects
• inhibits Nitrosomas and Nitrobacter
• direct health problems for fish

• control
• check bioload
• remove waste
• calcium rich substrate
• sodium bicarbonate
• temporary

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Increased PH

• effects
• ammonia is more toxic
• nonionized
• direct health problems for fish

• control
• check substrates for calcium rich ones
• peat moss
• acetic acid
• temporary

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Oxygen

• water0.7 dissolved oxygen
• oxygen solubility decreases as
• temperature increases
• salinity increases
• low oxygen effects
• respiratory distress in fish
• inhibits Nitrosomas and Nitrobacter

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Oxygen

• replenished by
• airwater interface
• aeration system
• monitored as DO
• Dissolved Oxygen

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Temperature

• preferred ranges variable
• 0 45 C
• temperature changes should be gradual
• no more than 1 C/ 2 minutes in tank
• no more than 2 -3 C between tanks

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Light

• light cycles
• 12/12
• at least 8-10/24 hours of darkness
• light source
• fluorescent most common
• no incandescent
• no direct sunlight

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Chlorine/ Chloramines

• toxic/ lethal to fish
• removal
• aeration and time
• sodium thiosulfate
• carbon filter

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Heavy metals

• toxic/lethal to fish
• sources
• metal pipes
• metal tank frames
• metal decoration
• saltwater
• extremely corrosive to metals

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Filtration

• mechanical filtration
• chemical filtration
• biological filtration

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Mechanical Filtration

• Physically traps suspended particles
• sand, gravel, floss, plastic,diatomaceous earth

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Chemical Filtration

• chemically binds and removes dissolved compounds
• charcoal, protein skimmer, UV, ozone

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Biological Filtration

• Nitrification
• bacteria
• substrates
• plastic, gravel, live rock, decorations

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BEHAVIOR
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Social Behaviors

• species specific

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Intraspecies Behavior
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Interspecies Behaviors
?
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Feeding behavior
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Environmental behavior

• geotaxis
• phototaxis
• electrotaxis
• thygmotaxis
• rheotaxis
• chemotaxis

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Reproductive system

• female
• ovaries
• oviduct
• no uterus
• male
• testes

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Fertilization

• External fertilization
• open-spawners
• substrates
• Internal fertilization

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Breeding

• females and males
• hermaphrodites

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Gestation

• oviparous
• ovoviviparous
• viviparous

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Spawning

• Control
• hormonal
• environmental cues
• seasonal
• Ovulation
• once/season
• more than once/season
• Inducible

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RESEARCH
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Research

• Advantages
• diversity-30,000 species
• easy to maintain in large numbers
• reproduce rapidly
• External fertilization/large eggs
• many species used
• Zebrafish, Japanese meduka

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Research areas

• embryology
• growth and regenertion
• genetics and transgenics
• toxicology and environmental monitoring
• neoplasia
• ocular
• pharmacodynamics
• physiology