Goldfish

You can assume that your 90 gal tank will actually be holding 75 to 80 gallons. The calculation is 1 inch of fish needs a minimum of 1 gallon of water so if you wish to do the right thing by your fish you will not use maximum stocking levels and should allow about 2 gals per inch of fish.

Aslong as it is a gradual decrease in temperature (i.e. not taking a fish from 60 degree water and throwing it into 33 degree water) the fish can survive right up to freezing water. In an outdoor pond setting aslong as an area below the ice for swimming remains unfrozen, they can survive.

Fancy goldfish (the ones with a rounder body and double tail) live for around 5-10 years depending on breeding and water quality. Common goldfish (with the more streamlined body and single tail) can live for around 20 years. Goldfish very rarely reach this age because people keep them in tanks and bowls that are too small. It is a myth that they grow to the size of their tank, this causes stunting which shortens their life-span considerably.
Well cared for, and in the right tank size, the life span of a goldfish can be 20+ years

Fish have nares, those little holes that look like nostrils on top of the mouth. The fish pass water through the nares and is analyzed by sensory receptors and the fish responds to those senses.

Yes... If they don't wash....

Salmon

There are actually several categories of freshwater/saltwater migratory fish.

Wikipedia breaks them up into several categories: Diadromous, Anadromous, Catadromous, Amphidromous.

See links for more information.

Some predators can also hunt in both saltwater and freshwater.

Sea Lions will enter rivers such as the Columbia River during fish migrations.

Bull Sharks are also known to hunt both in saltwater and in freshwater rivers.

Crocodiles have also been seen miles out to sea, scarily..

According to biologists, the protruding eyes of a frog help it to see all of its surrounding day and night. In addition, the eyes are water resistant and the frogs are able to rotate their eyes because they are unable to turn their heads around when detecting approaching predators.

What a very strange question. I would assume they do not hunt and catch goldfish to eat as a cat would. Neither can they dive and hunt fish as a Kingfisher would. So my guess would be that no, under normal conditions mice would not eat goldfish. They may eat one if given the opportunity, such as if the fish is dead and lying on the carpet.

no they eat freeze dried blood worms,live food,or Betta food bought from a store.

Yes. Depending on the fish, but all fish can freeze if the temperature of the water reaches a certain temperature.

It depends on what size you have. You can have upto 1inch of fish for each U.S. gallon.

that's probably a virus called "ick". My fish have had it many times, but only some have died if it's not taken care of. You should just go to the pet store and tell them you think your fish has ick and they should have a medicine you can put in the tank and it should disappear shortly.

plastic plants are not harmful to your goldfish aquarium.

To urinate, if you mean the urinary bladder. If you mean the swim bladder, it is to be able to change its depth in the water. It has a way to vent air from the gills to the swim bladder, and from the swim bladder to the digestive tract. So the fish would inflate the bladder to be able to rise and deflate the bladder to go lower.

Small community fish, 6 gallon tank is not much room for fish to move around once you include gravel, plants and other decorations, so you don't want any large fish. Platies, neon, black or glow-lite tetras. Standard rule of thumb is 1 inch of fish per gallon of water.

Goldfish like to be between 50F and 65F most of the time. During breeding season they spawn once the temperature gets around 68F to 70F. Over 75F they get uncomfortable and start to stress.

yes, you can bring a goldfish back to life if you rub jelly all over it and then sprinkle some sugar over it. This will then recall its sweet tooth and make it want to eat itself. Congratulations, your goldfish has been brought back to life.

They flick around the tank fast and move fast.

No. But if it is shedding for some strange reason, that means it has a body slime fungus disease.

Betta fish are pretty versatile. They could be in a cold water tank (not below 70 degrees) or in a warmer tank (upper 70's lower 80's) just, don't put them in cold then suddenly warm and vice versa, or, they'll die of shock. Also, they could be in a still water bowl or in a tank with bubbles. Although a betta can survive in a small bowl, a container of at least 2 gallons is preferable (a person could live in a closet, but would he want to??). Male bettas are "fin nippers" and so if placed in a community tank, avoid fish with long fins, like mollies or guppies. You must have at least 1 gallon of water per inch of fish, and provide plenty of hiding places.

Yes. Goldfish have been known to eat other goldfish that are small enough to fit in their mouth.

The suggested water space for goldfish is 20 gallons. You may have to separate them if they fight. The more goldfish you have in one bowl or tank, the quicker it will become dirty and it may require a change of water. Larger tanks should have a cleaning system, and possibly some snails or other way to keep algae off the glass.

Probably its water is rotten and putrid. Please do a water change ASAP and then use the following info. The fundamental rules for keeping any kind of fish are :- 1 inch of fish needs a minimum of 1 gallon of water. (more is much better) :- Every tank needs a permanently running cycled filter (it neutralises ammonia) :- Every tank needs at least 50% of its water to be replaced every week. (Keeps excess nitrate levels low) If you keep to the above rules your fish may stand a chance of survival. If you don't keep them I can guarantee that you will constantly have problems with your fishes health.

It depends on the size of the fish tank, the type of fish you keep, the filtration that you use on your tank, and whether you are using a bucket method, or have a gravel vacuum that attaches to a faucet