Goldfish swimming near top of aquarium

Question
I have a new very large aquarium and have introduced 6 fantail goldfish as starter fish 2 weeks ago.  Although they utilise the whole aquarium they generally like to swim near the top of the aquarium.  From reading things on the net, hope its not swim bladder or maybe its constipation. I feed them flakes and and tetra flakes.  Tried them on spinach - unanimously told me it was yukky!, corn: yes/no, peas: ok.  Very grateful for your suggestions

Answer
Hi Mattie,
Congratulations on the new aquarium! I bet all those fantail goldfish look beautiful and I bet they enjoy all the space!

It's ok for goldfish to swim near the top of the tank. The problems you want to watch out for are if they start to lose their balance or have trouble swimming in any way. Constipation can cause swim bladder disorder. But you usually -know for certain- when something is wrong.

Since swim bladder disorder in goldfish is most commonly related to diet. The best way to prevent it is to presoak any pellet foods you may feed to your goldfish. And sink the flake food below water so they gobble it up when it's already water-logged and they don't swallow too much air like they would when feeding at the surface. Most goldfish love vegetables like spinach, romain lettuce, zuchinni and peas. Zuchinni can be frozen and then thawed which makes the edible part much softer so the goldfish can get at it better. Leafy vegetables can be lightly steamed or blanched for softness. Sometimes goldfish won't realize it as really food but after a few repeated feedings, they learn to love it. And it provides them with very good amounts of fiber that all goldfish need as well as vitamines. Peas must be thawed and deshelled of course before feeding, and I haven't really found a goldfish yet that doesn't like them.
Goldfish also love sinking algae wafers, this food naturally softens up as the goldfish pick at it and a group of goldfish will push and shove to get a little bite.
And of course, goldfish can be fed small amounts of freeze-dried and frozen foods. But always in moderation. They don't need too much protein at one time.
Variety is most important when feeding goldfish.

Since your tank is relatively new, be sure not to overfeed since your bacteria colony is likely not yet established to handle too much ammonia. Just be very careful about feeding and wait until your tank cycles before adding anymore fish. Testing your water for ammonia and nitrites is the best thing you can do to determine if your fish are still safe and how far along you are in tank cycling.

I really hope this helps!
Best wishes,
Karen~