Sloan

I've got a 9 liter cold water fish tank with a filter and I kept 2 oranda goldfish (2-3 inches) ino a lot of people would say that is way too small but they lived for 5 months and died because my brother fed them for 5 days giving way too much food 😐 but I think wen it comes to cold water fish it's about how u take care of them and all that double filtration for small tanks is for people who don't care. I looked after two goldfish that I kept IN A BOWL!!! Ino that's really bad but they lived for a year and a half and again died coz my brother spilled a load of food in and then left... My brother is not great with pets..... But I've always had healthy fish and want the best for them so wat fish could I keep in a 9 liter tank that they would be happy? I was think cloud minnows or dinos (which I have also kept Befour in a bowl for 2 years) but wat would u suggest for me?