Hey all I'm new here

Yeah I just got some new comet goldfish last night about four of them, cute little guys.
Now before you think I hope he's planning on getting a bigger tank I'm making plans to buy a used
one or a tank that's one sale.
I did lose one of my little guys from some sickness or the thought he hurt himself when it was in
the tank at walmart. a tiny yellow spot was found under it's upper belly! I'm going to keep a close
eye on his other 3 friends.
What he was doing the night before I gone to bed, was iching up along side of the rocks it seem.
He might of had ick but I found no white spots and he didn't have that yellow spot then.
Now back to my tank plans... Right now my little guys are living in a 10gallon but what I could use is
some input/ advice on good tank size and how fast fish grow. I under stand in a year they get to be
3". I know a comet will get to be 12" it's adult size.
Yes I'm going to check the water for bad stuff soon

Jon