dwarf lionfish?

I have an extra 20 gallon tank and want to try keeping one of these.
Would he be ok in a 20 gallon tank?
Would a hang on back filter be ok?

 

IMO, no. From what I've read about them, they're not all that tiny and are heavy waste producers.

You might get away with frequent heavy water changes?

I don't know... can see what others have to say too.

 

I'm going to say no..

I'd say heavy water changes, a good skimmer, and decent amount of flow would work.

But if you're new at this hobby then go for a bigger system, more advanced system.

 

I think it's pushing it with a 20.

 

ive seen a full grown one. not even a 30 could hold it. sorry to tell ya :/