ok so today is my fiences and my 2nd anniversery and i have been begging him to let us get a fish so today we bought one. we got a black moor goldfish, and as i find out now hes apperently a very clumsy fish so it was good that i got him this little round bride that he can't poke his eyes on and he likes to go under it and stay for a little while but we got him a two gallon tank becasue thats what the lady at the pet store said he would need, but now im looking online and seeing he's going to need a lot bigger tank....? also to make it easier for us to clean and better for him can those little sucker fish go in the tank with him? and should we get the little plants for the tank to help with oxygen because i know he likes to digg so im kinda afraid he'll uproot the plants and end up hurting himself somehow.... i really have no idea, and id be really grateful for any help anyone has for me thank you so much
but if you would like to keep more fish (either different fish or another black moor), then at least now you can sort out everything properly. If the tank is still brand new, you could take it back to the shop and swap it for a bigger one. Then if you do a fishless cycle (where you add household ammonia to the tank) then in a couple of months you should be able to add a new fishie without having to worry about him (or her) getting ammonia poisoning 
(he did say so in another thread!)