Goldfish behaviour question

Last weekend I bought two goldfish (a shubunkin and a comet) for my kids. They are in a 14l tank. They seem to spend a lot of time nudging each other, sort of bumping into each other’s side. It doesn’t look confrontational.

What is this? Aggression? Play? Mating? Is one of them going to harm/kill/eat the other? My kids would be distraught.

Isn’t 14 liters, like, 3 and a half gallons? That’s nowhere near enough room for goldfish. They’re messy fish that produce a lot of waste; they need a lot more water than that.

I have had goldfish breed before, and thats exactly what they do. They swim next to each other and bump each other, I guess to knock the eggs out of the female.

However, they never did it in a tank that didn’t have lots of room and floating plants. So, maybe not?

Well, I asked the guy at the shop how many to get for the tank size and this is what he told me. There seems to be plenty of room as far as I can make out. In fact, what puzzles me is why they get right on top of each other when there is room to swim around.

This has been more or less non-stop for the last week. If they are mating, well, they are certainly very eager. Cue awkward questions from my children.

No shit? Wow-- I’ve heard that it’s extremely rare for goldfish to breed in captivity. That must have been neat to watch.

I’ve heard that some fish are extremely sensitive to tactile sensations. Supposedly a shark blows a fuse or two if you gently rub his nose. (I’ve seen video-- they go perfectly still as if mesmerized.)

Maybe your fish are doing it because it provides a pleasurable sensation that they can’t get from rubbing against rocks and the like. Perhaps it has a social aspect to it.)

14l tank is awfully small. Your location isn’t set, but in the US a lot of tanks that would be labeled 14L mean 14-gallon tank long configuration. As opposed to 14H for example.

No, it’s definitely 14 litres. This is it. Though it looks smaller in the picture than in real life. The same company makes a 10l one and I think that’s the one in the picture.

So what happens when they don’t have enough room? Could that account for their behaviour?

If they don’t have enough room they poison themselves. Did you cycle the tank or just dump them in there? In a balanced fishtank, the fish excrete ammonia and bacteria turn it into nitrites, and then other bacteria turn it into nitrates - in other words, all the ammonia gets eaten. In a non-balanced fishtank, like if you just set it up and drop the fishies in, there’s a lot of ammonia before the bacteria get up and multiplying. A hardy fish can survive it, but not all do, by far. That’s why a lot of people get “new tank syndrome”. Remember, it’s not just like when your dog pees and you step in it on the floor - these little guys breathe this stuff.

Just to echo what others have said here, the minimum of space needed per fish is 1 gallon per 1 inch of fish. And without proper cycling, these guys are probably going to die real soon.

I’ve tried pretty hard to be responsible.

I bought the tank a few days before adding the fish and followed all the instructions. I added a capful of something called “Nutrafin Cycle”. So, if that counts as cycling the tank, then I did do this. I’ve also replaced 2l of water twice so far as the instructions said to do this a couple of times in the first week.

Does one of the fish have a white “bump” sorta thing by its butt? If it does, that indicates eggs.

When the eggs come out they are pretty much transparent, and will be stuck to the rocks and plants and stuff, but, if you don’t get the fish out of there, the parents will turn around and eat them.