Unless you expect it to just swim around in a bowl. It helps to CLEAN IT every once in a while.
You can only kill a goldfish once. The sentence suggests it is possible to kill it more than once.
The dragon goby is semi-aggressive, but mainly feeds by sifting organisms out of the mud. In general, like most fish, they will eat anything that fits in its mouth. A fancy goldfish can reach 10"-12" and a dragon goby can reach 24". It would seem that once the goldfish reached a large enough size, it would be safe. I would not put a 2" goldfish with a 24" goby.
None. Goldfish are egg layers so they can not get pregnant. They will spawn once a year under normal circumstances and they live for more than 20 years if properly looked after.
A hamster can have up to 16 babies at once but the average hamster has about 3-10 babies
Baby goldfish, once hatched from their eggs, are called fry
Goldfish "spawn" they do not get pregnant because they are egg layers and the eggs are fertilised after they are released from the females body. Goldfish will eat their eggs if they can find them, so either the fertilised eggs or the goldfish should be removed once 'spawning' is completed if you wish to raise some of the young. BTW 1 goldfish spawning can produce many thousands of babys.
No because the coy is a fast growing, aggresive fish. The goldfish is a slow moving fish and very docile. The coy, once it outgrows the goldfish will start to eat the fins and constantly attack them. I have seen it happen many times with people who think they mix well. They will however live together in a large outdoor pond if there is enough room, food and cover.
it lays about 10,000 eggs at once
Once a week :))))) i have experience
Once a year.
Yes, you can. I did it once