What Size Tank Would I Need For These Fish?

[Betta5]

Hey, Im still not decided 100% at what I want to do marine wise yet but im getting there. Seeing as im doing a fish only, I thought it makes sense to go quite big, well bigger than my freshwater tanks. So I can keep more interesting fish. Annnyway, I have a few questions. Im thinking of a 4x2x2, But im thinking most of my choices wont work in less than a 5x2x2 would any of these not 'fit'? Also would any of these fish have problems together?

Can you keep a saddleback butterfly (or any butterfly fish really) fish in a fish only system? I saw one at the pet shop today and it was so cute!

Picasso triggerfish, Now i know they can be agressive but they are just such a cool looking fish, it would be great to own.

Yellow and regal tang. Can these be mixed? Will they fight?

Could I keep a group of about 6 smaller fish like chromis or damsels?

thats all I can think of at the moment.

What would you stock in a 4x2x2?

thanks

 

[Betta5]

The bare bones of the system would most likely be

5x2x2 tank
Normal lighting
Big external filter
V2 600 skimmer

 

[ben1987]

Bigger is obviously better. Butterflys are actually probably better in a FOWLR as they eat corals. But they are hard to keep well fed as they are picky eaters. Those tangs would be ok together on most occasions. its is down to the individual fish though. Best to add those two quite small and at the same time.