How many pairs of clownfish on a 400g tank?

[souk]

You can try but keep but keep an eye on them since it's a big setup. Also, to late now but it's always best to add them at the same time.

I have a 80 gal(48x24x16) with a breeding pair of onyx and a pair of juvi flakes. They get along well except for the little flake which is always up to a challenge and at times does not want to back down. Don't know about a rule but they get along just fine.

 

[goat585]

I have 2 pairs in my 240 gallon 4x2x2'. A pair of ocellaris and a pair of Onyx perculas. They were aggressive to each other at first but have calmed down. Currently they all hang out in the same area together. It can be done but you have to be able to handle the situation if they do not work out. I have extra tanks and breeder baskets around so if I have to pull them I am able to. In a tank your size I would consider trying it if you are willing to deal with the risks. My pairs are all tank raised (by me) so that may contribute to better success then wild pairs.

 

[OrionN]

If you have immature clownfish of the speices that are not agressive, you can keep multiple togeter but Clarkii, Tomato, Maroon, Saddleback, Blackfoot are not easity feasible. Female of these species are very agressive and will not tolerlate other clowns other than their mate around.