I hate to tell you this but a 65 liter tank (roughly 18 gallons) isn't big enough for one fancy goldfish much less 3. I've kept goldies and they are large, dirty fish that produce copious amounts of waste. They may be small now but they can grow a lot in the first year. You would do yourself and the fish a big favor by finding them a home with a proper sized tank which IMO
would be about a 50 gallon for the 3.
As for the 25 liter (6.6 gallons) the only thing that would work in it would be some little nano fish such as Scarlet Badis, Clown Killifish, Ember Tetra's, Chili Rasbora's, just to name a few. Or you could do a shrimp tank.