Advice on tank type for euphillia build.

[Clowns-corals-cats]

Just looking for some input on a decision I have to make Friday. I've been planning a build for awhile headed to the city Friday to pick up the start of things. It's going to be probably %75 euphillia with a single maroon clownfish. I really want a 20-40g long tank but can't decide if it would be better do get a cube instead.

 

[Spare time]

Tank shape is up to you. The right flow is usually what I find makes euphyllia the happiest (as well as proper par levels)