I would wait till the fish pass away before adding goldfish, or rehome the fish you have when there better.
How many gallons is the rio 180?
If you have another tank yes you can take a mature filter sponge from another tank.
But only once you done water changes and run some black carbon.
How many gallons is the rio 180?
If you have another tank yes you can take a mature filter sponge from another tank.
But only once you done water changes and run some black carbon.