Why are my goldfish acting strange?

New fantail goldfish acting strange?

• Can anyone tell me what's wrong with them? I bought a new 30 gallons or 110 liters fish tank and cycled it for two weeks. I bought two new goldfishes a week ago. The first three days they were acting pretty normal. But from the fourth day onwards, they were acting really strange. It's like they're on speed or something. They spend most of the time in a corner, trying to nip on the glass. They also swim around unusually fast, acting very nervous. The fins are fine, I don't see white spots and they're eating the food. Before I bought them I had the water tested in the petstore and they said it's fine. I had it tested again yesterday and it's still fine, they said (they run only 1 test, probably Nitrite). I asked them about it and they said I should monitor this and let them know, but I'm not sure.

• Answer:

  They are fine just very nervous if you haven't you should get a mini cave or something for them to hide in then see how they are.