1. 8:31 Class: Osteichthyes - Bony Fish

2. As Chordates, fish have an incredible variety of characteristics.
Eel
Sturgeon
Sea Horses

3. Most are covered with flat scales that fit into pockets in the skin and have a mucus coating.
Some lack scales or have tiny scales. Scales may be cycloid, ganoid or ctenoid types. Some can be reabsorbed if food is scarce.

4. Scales contain chromatophores that cause color changes for camouflage, mating - species recognition or when stressed. Iridocytes contain reflecting granules.
Photo: Betty Newton

5. Ctenoid Scale
Cycloid Scale
Placoid Scale -Sharks
Ganoid – Gar, billfish

6. Symbiosis aids in reef fish survival.

7. Circulation: 2 chambered heart, most ectothermic
Cryptic coloration: false eye on butterfly fish, kelp fish; counter-shading, (dark on dorsal surface and light on ventral); camouflage; aid in survival
False eye
Circulation: 2 chambered heart, most ectothermic
Tuna, barracuda and a few others maintain temperature higher (~10o) than environment so technically they are endothermic.
false eye

8. Gills help regulate the salt/water balance called osmoregulation.
Respiration: Water containing 02 flows over the gills in a different direction than blood so diffusion is maximized; muscles pump water through gills
Gases from the blood and/or gulped air are used to adjust buoyancy in the swim bladder.
Several gill arches supporting gill rakers and gill filaments are covered by a flap called the operculum.
Gills help regulate the salt/water balance called osmoregulation.
NOAA

9. Vision: Poor to medium and usually only lateral
Vision: Poor to medium and usually only lateral. The iris is not adjustable and lens protrudes through the pupil.
Some fish can detect and generate weak electrical currents.
This electro-perception is used to communicate in schooling, aids in migration, detecting and stunning prey.

10. Hearing: Aided by the lateral line, the swim bladder and the otoliths (located in the inner ear) detect movements and affect balance.
Smell: Chemoreceptors are found on the mouth, lips, skin and fins.
Most of brain is olfactory lobes use for smell to find food.

11. Reproduction: sexual, mostly external fertilization called spawning
Gonads - sac contains either sperm or eggs (roe).
Sex reversal is common in reef fish.

13. The roe of sturgeon fish are harvested for caviar.
Aquaculture provides for several farm-raised species such as sturgeon, tilapia, catfish, and salmon.

14. The red blood cell count in tuna is equal to mammals.
NOAA
The red blood cell count in tuna is equal to mammals.
Tuna are exquisitely designed for speed and can swim at 45 mph for long periods.
Bluefin tuna and sailfish are the fastest fish at nearly at 70 mph.

15. The largest bony fish is the Mola Mola (Sunfish).
Molas are planktivores and can weigh 3000 pounds when up to 11 ft. long.