It depends, if the goldfish are all males (or females) no, but if not of course they can mate.
Yes, goldfish are very messy. Goldfish need 10 gallons per fish, you actually need a 20 gallon tank or about a 70 liter tank for 2 goldfish. But the small tank will do while they are small, you will need to eventually get a larger tank.
Not happily or healthily. Those goldfish need at least 30 gallons of space to live happily and have a long life. If you do successfully breed your fish, remember to remove the babies ASAP. Goldfish like to eat their babies.
Yes, but your tank size needs to support it. If you mean that a regular goldfish is a long single-tail goldfish, then you need at least a 40 gallon tank just for the 2 fish due to the size potential of the common goldfish. If you mean a regular goldfish as in a round bodied fantail, or perhaps a ryukin, then you need at least a 30 gallon tank for the 2 fish.
Regardless of the type or size of goldfish the minimum acceptable size of an aquarium for a goldfish is 30 gallons. Buy a tank that is at least 30 gallons if you plan to have goldfish. You can comfortably fit 3 goldfish in a tank this size but no goldfish in a tank any smaller. Goldfish are essentially pond fish and need lots of space to swim; they will not thrive in a small aquarium.
One goldfish needs a 30-gallon tank, and an additional ten-gallons per additional goldfish. Goldfish can grow to be 10-12-inches long.
yes you can
No, Neon Tetras and Goldfish do not belong in the same tank. Goldfish prefer cold water, while Tetras are more of a tropical fish.
2-13
bassicly the one that started the attack you need to put it in another tank for a few days
NO U WILL KILL IT!!!
A total of four mollies can be found in the water tank
You cant. Goldfish need much bigger tanks. 20-30 gallons. I bought 2 goldfish when I was new to aquarium hobby and put them in a 5 Gallon tank. The first one died in just one and a half day. The other one died just hours after the first one :( So if I were you, I would get a bigger tank.