Ventral heart, with dorsal and ventral blood vessels and a closed blood system 6. Complete digestive system 7. Bony or cartiliaginous endoskeleton usually present 8. Most fish do not seek food, they seem to wait untill food appears, then move to get the food. Fish are covered in scales so that the can move more agile in the water.
Most fish are similar in the way the they move and act.
Though each species of fish have a specific body type, the contitions where they live, and what color their scales are.