Goldfish in small tank

[Lucero]

My mom impulsively bought goldfish while we were getting cat food, I had strayed off to look at the cats. Go back when she's checking out and see she bought goldfish

We get home, I start researching them to make sure we bought everything. And turns out the employee told us the wrong size tank and told us not to get any substrate because it's just for decoration

We bought a ten gallon tank for two goldfish(pretty sure they're just babies atm)

They're not my fish so I can't just buy a bigger tank for them or put substrate

Is there any other way I can help? I tried telling my mom this won't work and she said "they're just fish!"

[Delapool]

Hi, unfortunately not long term - I’d imagine tank not cycled either I guess? Any chance of swapping at store?

[Lucero]

She just bought a tank and filled it with spring water from Wal-Mart. She won't try to get a bigger tank because she thinks there's no point in it because we had fish when I was a kid in a way smaller tank than that (they all got fin rot and died because she didn't notice it)

My ex told me to get an airstone and put it in the tank with them so I might try that? but I just live with her.

[Lucero]

My mistake, it was mouth rot I think. I just know they had white patches all over them

[1midniterider]

Get a kit to measure ammonia, nitrite and nitrate levels. Personally, I'd add pebble substrate, an inch or two deep. Be prepared to perform frequent 25% - 50% partial water changes. To keep the ammonia in check. The tank will need to cycle to build up the bacteria to convert the ammonia from fish waste and leftover food to its less harmful form.

[Lucero]

I can try to get a kit but she won't let me put any substrate in there because "it looks bad" and "it's hard to clean!"
Trust me, I've told her the reasons why she should have it in there

[1midniterider]

With the kit you will be able to monitor the situation.

[King Fisher]

Get a couple air driven sponge filters and put them in the back corners. You can run a bare bottom. Your mom is going to have to change out about 1/3 of the tank water every 2-3 days since it isn't cycled. Don't overfeed.