### animal | vertebrate | fish:

Bony fish
* All bony fish have gills and for most species, gills serve as their main organ for respiration
  - skeletons made of bone
* Many bony fishes change color to advertise their readiness to breed
  - reproduce once a year until they die
  - spend most of their time lying on the ocean bottom
* Most bony fish are neither electrogenic nor electroreceptive
  - ray-finned
* Most bony fish have a swim bladder located beneath the backbone
  - bladder, which is an internal organ that is filled with air
  - bony skeletons
  - external fertilization and external development
  - lobes
  - shape vertebrae
  - sides
  - stiff skeletons
* Most bony fish live in salt water
  - possess caudal fins
  - utilize a gas-filled swim bladder for buoyancy
* Most bony fishes are oviparous and spawn their eggs for external fertilization
  - ray-finned fishes
  - become sexually mature between one and five years
* Most bony fishes have a fusiform body shape
  - more efficient mechanism to bring in water to the gills
  - single pair of gill openings
  - mouths at the front end of the head
  - small home ranges
  - reach sexual maturity between one and five years
* Some bony fish can detect weak electrical fields through pit organs on their heads and faces
  - develop lungs
  - feed on crabs
* Some bony fish have calcium phosphate
  - problems
  - use their swim bladders for breathing air
* Some bony fishes are quite specialized for feeding
  - sexually mature at birth
  - bear live young that can protect themselves at birth
  - become sexually mature shortly after birth
* Some bony fishes can go long periods without eating
  - tolerate high salinity levels
  - display complex mating rituals
  - have soft, flexible fin rays
* Some bony fishes have symbiotic relationships with non-fish species
  - with nonfish species
  - lay eggs that drift through the water column
* appear to rely on vision more than most cartilaginous fishes.
* are fish.
* are found in both salt water and fresh water
  - marine and fresh water
* are the largest group of living vertebrates
  - most numerous and diverse of the vertebrates
* comprise the majority of fish in the world except the sharks.
* continue the ring breakage by forming allantoic acid.
* depend on color vision to detect both rivals and mates.
* exist in fresh water, seawater, and brackish environments.
* fertilizes either internally or externally.
* have a backbone and a skeleton made of bones
  - gas filled swim bladder that they use to control bouyancy
  - hard, bony skeleton
  - operculum or gill cover that pumps water across their gills
  - chloride cells, that filter the salts balance
  - gills that collect dissolved oxygen from the water
  - separate incurrent and excurrent nostril openings
* inhabit almost every body of water.
* is fish
  - waters around the world
* maintain levels.
* posses swim- bladders which are filled up with gas or air.
  - otoliths
* reproduce sexually.
* secrete a layer of mucus that covers the entire body.
* share many characteristics, as indicated in the following illustration.
* show various degrees of fin fusion and reduction.
* use a swim bladder to maintain neutral buoyancy.
+ Electric fish: Fish
  * An 'Electric fish' is a fish that can make electric fields. Fishes that can generate such fields are said to be 'electrogenic', those that can detect them are called 'electroreceptive'. Most electrogenic fish are also electroreceptive. Many fish, for example sharks, rays, and catfishes are electroreceptive. They cannot generate electric fields though, and are therefore not classified as electric fish. Most bony fish are neither electrogenic nor electroreceptive.