She set this up like many who don’t know much of anything about fish keeping she doesn’t even know what parameters are so I’m sorry i can’t get those, here is a picture. And no it’s not a baby tank
Just to see if i got this right...thats a 10 gallon tank and those fish are at least a year old?? They look a little on the small side. I dont know what's wrong with its eye. But I do know that i have a small fish, I don't know what kind it is, but it's had several bumps on it for over 8 months now. I seperated it from the other fish as soon as i noticed it. I honestly thought it would end up dying but it never acted sick and hes still alive. I even put another fish in with him about a month ago so he'd finally have a friend and that fish never caught anything from the first one. If those fish have all been together since that formed on his eye a year ago i think its safe to say they probably wont get it. Sorry I'm by no means an expert of any kind, thats just my opinion. As for the goldfish tank. I have 3 of them myself. That 10 gallon tank is too small for even one goldfish.
If your friend has them in that tiny tank because they can't afford a bigger one at the moment they can go a temporary route thats cheaper and buy them a big plastic tote until they can save for a bigger tank. A 55 gallon tote or tank will work for now maybe even a 40 since they're still small, but they'll eventually need a 75 gallon to house all 3 of them. Of course thats the minimum. They can always go bigger if they want. But they really need to get out of that 10 gallon ASAP.
But if theyre in the small tank because they dont have the space for a bigger one, it would probably be in the best interest of the fish if they rehomed them to someone who can provide all the necessities for them. And if your friends still want fish they can always get a few guppies or similar sized fish that will stay small.
Goldfish get pretty big and no matter what size they are they still produce more waste than any other fish breeds. Its best to get a filter thats made for a larger tank. If you put them in a 55 gal you should get a filter thats for 100 gal tank or even more.
But seriously if they want to keep them I know a tote doesn't look all that glamorous but its still better for their health to be in something much bigger than what they're in now.
My 3 goldies were rescued from a bait shop and brought to me and i was completely unprepared for them. They spent less than a week in the 10 gallon tank with water changes 3 times a day because I had no filter. But I moved them to a 40 gallon tote as quick as I could. It wasn't pretty but they were much happier. My fish are probably around 1 and a half years old now and they're pretty big. They were fairly small when they were brought to me and they've at least quadrupled in size in less than a year. Give them a good variety in their diet. Mine eat small pellets now because they've outgrown the flakes and they love peas. Get a small bag of fresh frozen peas NOT canned. Thaw out a few of them. I just thaw mine in hot water. Always remove the outer shell, or hull or skin or whatever the outer layer is called. Just pinch a little piece of it to make a hole and you can squeeze the pea right out. Break them up in small pieces and watch them devour them. I give them peas once a week and also alternate back and forth once a week between blood worms and baby shrimp and of course pellets twice every day. First things first tho and that's to get those babies in a bigger tank. If you get a tote its best to get the harder plastic ones that the sides stand as straight up as possible. I learned the hard way and the sides ended up bowing out and the filter wouldn't hang right on it so i had to continue with the daily water changes until I had something more solid to hang the filter on. But anyway best of luck to your friends and their fish. I hope this helped in some way. I would love to hear a future update on them.