Mbu Puffer With Fly river turtle

possibly might just use the turtle to trim its teeth

good luck with that. I personally wouldn't try it. a 300 dollar mbu meal doesn't seem worth the risk. not to mention puffers are extremely messy fish, especially when they get 18 inches long, and require lots of water changes. Turtles are also notoriously dirty. Puffers are very sensitive to ammonia, much more sensative than most other fish. even the very low levels will have a noticable effect on their behavior and eventually will kill them. Believe me an mbu alone is plenty enough to make an amazing tank.

What size tank will this be?

With one creature being messier than the other (both extremely messy!) I would consider this only with a several thousand gallon system, large sump & multible veggie filters.

This setup would need a HUGE tank.......

what size tank you gonna use?

Most people will not be able to tell you. It will really depend on the temperment of the puffer. I have yet to see a vicious Mbu, but I haven't seen one past 12".

That beening said, I would try it when I had a chance to watch the setup for a few hours (maybe while reading TFH and glancing up every once in a while). Agression will usually take place quickly or not at all.

I have a guppy, a bristle nose pleco, and a convic with one of my fahakas. They are all in danger of being killed, but I am interested in how long it will take.