Dont jags grow to the same size as doviis?!I do not have one, I do not have a big enough tank for one. thought I had made that clear. If not I am sorry, my mistake. I do keep jags. I have the tanks for that.
Each to there own with suggestions on what size tank they should keep for their fish in, obviously common sense would prevail when the fish gets bigger. But just because your opinion on what size tank I should keep a dovii in shouldnt stop me or anyone else for that fact that wants to keep a dovii. My tank is a decent size and its not like its a 30 or 55 gallon. If I choose to keep this dovii and he blows up to be an absolute monster than obviously I would have no problem upgrading to a bigger tank, or find a more suitable home for it. How else are you going to build experience?
There is a video of a massive 22" costa rican male dovii on youtube thats kept in a 180g tank looks very comfortable with ample of room.