I recently tried to introduce a group of small clowns to a tank with an established couple but it failed miserably due to a deadly outburst of brooklynella.
Here's the 400 liters tank with the surviving clown trio

The trio has been peaceful for a few months but odds are that that family arrangement won't last.
I am faced with 2 options:
- Let the trio stay while there's peace and find a new home for the smaller clown as soon as I see that he's no longer welcome in the group;
- Accept the offer of 5 young clowns from a friend. In this case, I would remove all the fish from the main tank for a couple of days and reintroduce them all at once.
What are the chances of the last option in the long run?
Here's the 400 liters tank with the surviving clown trio

The trio has been peaceful for a few months but odds are that that family arrangement won't last.
I am faced with 2 options:
- Let the trio stay while there's peace and find a new home for the smaller clown as soon as I see that he's no longer welcome in the group;
- Accept the offer of 5 young clowns from a friend. In this case, I would remove all the fish from the main tank for a couple of days and reintroduce them all at once.
What are the chances of the last option in the long run?