Puffer For A 40 Breeder

HI guys, I've been gone a long time. first post in nearly 2 years I believe.
So I've got this 40 breeder and I want to do a puffer. Ive kept the dwarfs before and sense it's a bigger tank I'd like to do something with a bit more umph to it. I don't mind doing brakish if need be, as I am no stranger to salt though I would prefer freshwater. That being said I'd like to do something other than figure 8 or green spots.
I also want one that's going to be pretty active rather than one that buries itself in the sand or hides all the time. I belive it's the red eye puffers that often do that? Correct me if I'm wrong.
So anyone have any ideas?

 

Tetraodon schoutedenI Spotted Congo Puffer. Very laid back all fresh water. Have to open your pocket book a little. Mine is awesome though.

 

Tetraodon schoutedenI Spotted Congo Puffer. Very laid back all fresh water. Have to open your pocket book a little. Mine is awesome though.

Lol seems like opening it 300 dollars worth. I don't think that'll be happening...

 

You can get them 125ish

 

So I work for one of the large pet corporations as the aquatic specialist (I'd rather not say which one but it's a big COmpany) and yesterday we received fish. It just so happens that 3 figure 8 puffers came in. So I took it as a sign and decided to take them home.
Honestly they'll be better off with me where they can be cared for a bit better
So I'll update here as we go.

 

Any updates

 

Well one of them wasn't doing so hot and didn't make it. The other two were nipping at each other a good deal so I picked my favorite and rehomed the last guy.
Sense the original posting I've added 2 hog chokers ("freshwater" flounder) and a bumblebee gobee.
Alls going well but I am concidering moving them to a slightly smaller tank sense there is now only one puffer. Main thing holding me back is the very limited information on the hog chokers. I've heard everything from 4 inches to 9. That being said I went to the national aquarium in Baltimore on Saturday and they had several freshwater flounder at around 4 or 5 inches, in massive tanks at that.
Slowly adding some salt to the tank, no rush everyones young enough. Also I put in an air stone, as I am running a Marineland internal canister which was providing no surface agitation resulting in a slight film. Other than that no problems. Everyones eating like champs, as far as I can tell anyway.
Sorry, that was a long one. But hey its been a while.