need suggestion for clown juvenille tank

[Tsunami]

In your opinion, what is the best type of tank to keep post metamporphisis/ juvenille clowns?
currently I have them in a 10 gallon with no filter.
What are your suggestions based on your experience?
I am aware that any filtering may need to be appropriately modified so as to not such the little guys up.
thanks for you input!

 

[Slakker]

Perhaps a 10 or 20 with an established sponge filter?