How does a rainbow fish stay safe?

Which ocean do jellyfish live in? How do hermit crabs die without a shell? What color is feushia? How big is colossus the shark? What is the Bull sharks Range? What does a stink ray eat? Are whale sharks nocturnal? Is there still sharks in Alcatraz? How old do fantails get? My blackmoor fish is attacking my other goldfish i have a 30 liter tank the water is clean and i have a good filter it has killed one alread my brother is very upset why is the black moor doing this? Do dolphins eat sharks? What was the diet for a megalodon? Would anyone want to buy your yellow pure strain baby guppies they r round a month old now? What level does Gulpin evolve at in emerald? Which practices can be used to protect our supply of freshwater? What is the fiddler crabs phylum? Do you let new water sit before you put it in the fish tank? How much salmon for toddler? Can piranhas bite through bamboo? What kind of fertilization do most fish have?