gouramis keep fighting. Will adding more fish stop this?

Well what the pet store is suggesting is adding dither fish, and yes this does work.

What happens is the Gouramis spend less time chasing and bothering each other and more time chasing the little fast fish. I wouldn't use guppy's though because they aren't very fast and they will get beat on with their long tails, as well as bring another level of aggression into the tank if you get males.

The Only thing is though 60 liters is only 15 gallons, that's not enough space at all for your two Gouramis that will both get 5 inch's. Plus its very well noted in the fish keeping world that gold gouramis are very aggressive fish. So adding more fish won't make that problem go away in such a small tank.

My advice is tell your cousin to take one of the gouramis back and get a small shoal of tetras to liven up the tank.

Good Luck

Edit: Sorry to correct you boom$ but adding a third Gouramis that gets 5 inch's is not gonna help the problem, its gonna make it worse. That's only a 15 gallon tank, that's why they are fighting, adding more gouramis is gonna make it worse not better. Two of them will just team up on the other or one will beat the other two into a stress related death. Not a good Idea at all.

The store probably suggested that so they'd get some more money by selling more fish. It will only mean that other fish get caught up with the fighting.

Rehome one of the Gouramis. Blue/Gold Gouramis are often the same species only different colour forms and one of the more aggressive of the Gouramis. The tank she has these in is not huge and these guys get big at around 5"-6". If they both made it to adulthood that'd be a pretty big chunk of fish to be fighting! Is she sure she bought male/females? Two male Gouramis can fight to the point one dies. They are highly territorial animals.

I would recommend she rehomes one. Problem solved.

Gouramis are a type of anabantoid, meaning that they are a top-dwelling fish with a labyrinthine organ. Anabantoids are also pretty territorial. They don't like to be around other anabantoids.

I suggest either returning one of the gouramis and replacing them with some new, non-anabantoid community fish (some corydoras or some smaller tetras like cardinals).

Indian Gourami

No adding smaller fish won't help.

But adding another Gourami will.

With only 2 gouramis they are fighting over territory.

With three gouramis they will stop fighting because there will be no territory issues.

Hope this helps!

Good Luck!