Fish Medicine Flashcards
What are a majority of ZCA species issues related to?
husbandry
What are the 2 major classes of fish?
- Chondrichthyes - sharks and rays
- Osteichcthyes - Actinopterygii* (ray-fins), Sarcopterygii (lobed fins)
What are the most common fish species presented to veterinarians? What are the 2 major families?
freshwater (ornamental) teleost fish
- Cyprinids = koi, goldfish
- Anabantoids = bettas
What are the major anatomical adaptations that fish have made to their environment?
different body shapes
- fusiform (torpedo)
- ribbon-like
- eel-like
- ventrally flattened
- spheroid
- laterally flattened
Where is the coelom found in laterally flattened fish?
right behind the operculum, which covers the gills
Label the following anatomical structures of the fish.
a. lateral line - sensory, venipuncture landmark
b. dorsal fin
c. caudal peduncle - cranial to caudal fin, venipuncture landmark
d. caudal fin
e. anal fin
f. vent
g. pelvic fin
h. pectoral fin
i. operculum - bony plate covering the gills
Where is the heart located in fish?
caudal and ventral to the gills
What is the physical barrier to the environment? What is it responsible for?
integument
- hydration
- osmoregulation
- other physiologic functions
What do alarm cells and chromatophores in the skin of fish do? In what 3 ways does their skin differ from mammals?
ALARM CELLS = secrete a substance when skin is penetrated to alert other fish of danger
CHROMATOPHORES = change color of skin in response to physiologic stimuli
- epidermis lacks keratin
- all layers are capable of mitosis
- minimal to no SQ space
Chromatophore action:
How are injections given concerning fish scales?
under/between —> can cause damage and infection if directly through scales
What is the cuticle of fish skin?
mucus layer on the surface of the epidermis responsible for immune defense and UV protection
- contains Igs and antimicrobials, commonly fed on by fries
What is the primary mode of respiration for fish? What 2 additional functions does this system have?
gills —> requires continuous flow of water (swimming!)
- osmoregulation
- excretion of nitrogenous waste
Gills, histology:
What is the heart and lymph system of fish like?
four chambers - sinus venosus receives deoxygenated blood, atrium, ventricle, bulbus arteriosus sends off deoxygenated blood
has an extensive system that lacks nodes
What 3 systems take part in osmoregulation and excretion in fish?
- gills
- kidneys
- digestive tracts
What are the 2 anatomical sections of fish kidneys? What are their functions?
- ANTERIOR - hematopoietic, endocrine, area for blood collection for cultures and histopath
- POSTERIOR - hematopoietic, excretory
How does osmoregulation in freshwater and marine teleost differ?
FRESHWATER - must remain hypertonic compared to the environment, so they actively uptake and retain electrolytes and produces dilute urine
MARINE - must remain hypotonic compared to the environment, so they take in more water and actively excrete concentrated urine
How does the GI system of herbivorous and carnivorous fish compare?
HERBIVOROUS = longer tract
CARNIVOROUS = shorted tract
(some fish contain a hepatopancreas + GB and lack a stomach)
What is the nervous system of fish like?
similar to other invertebrates, contain a CNS and PNS —> they feel pain!
What is the lateral line system?
sensory system containing mechanoreceptors and hair cells that is sensitive to vibrations and water displacement
- how fish are able to form such tight schools
What is head and lateral line erosion (HLLE)? How is it treated?
depigmentation and decreased function of the lateral line up towards the head, common in saltwater fish (tangs!) kept in tanks with recirculated water
improve tank water circulation system
What is the swim bladder?
organ present in some fish responsible for buoyancy, pressure, and sound production (drummed against)
What are the 2 types of swim bladders?
PHYSOSTOMOUS - contains a pneumatic duct between the esophagus and swim bladder allowing the fish to swallow and burp out air to actively alter buoyancy
PHYSOCLISTOUS - lacks a pneumatic duct, making the fish unable to quickly change buoyancy
What are common causes of buoyancy disorders in fish? How are they treated?
- granulomatous disease
- polycystic kidney disease
- fluid within the swim bladder
- poor water conditions
- congenital
- decreased temperatures
high fiber foods (peas!), mechanical devices, antibiotics, aspiration of the swim bladder
What are important aspects of a history taken during physical exams on fish?
- TANK: size, lighting, filtration, heater, feeding, decorations, length of ownership
- WATER: source, frequency of change, water quality
- TANK INHABITANTS: types, numbers, diet, frequency of feeding
- CURRENT PROBLEMS
- PRIOR TREATMENTS
What is the major cause of illness in fish in human care?
water quality issues
What are the 3 types of filters used in fish tanks?
- MECHANICAL - foam/sand physically removes/traps particles and debris
- BIOLOGICAL - bacteria in the filter breaks down nitrogenous waste (drugs used in tank can kill these bacteria)
- CHEMICAL - ion exchange with carbon and UV lights sterilize the tank
What are the 7 basic water quality parameters measured during physical exams?
- temperature
- dissolved O2
- ammonia
- nitrite, nitrate
- pH
- salinity, hardness
- chlorine, chloramine
What are 4 abnormal behaviors that can be observed in fish?
- flashing - rubbing against substrates or decorations = parasites!
- piping - gasping for air = O2/water quality problems!
- clamped fins - not moving and keeping fins close to body = uncomfortably, not systematically well!
- isolation or congregation
What external lesions are commonly seen in sick fish?
- pigment changes
- lesions
- deformities
How can obesity be differentiated from ascites (Dropsy)?
ascites will cause scales on dorsum to protrude