Ropefish sometimes get over thirty inches long but they grow fairly slow and are eellike in form. Personally I would have no qualms about keeping one in a 20g unti it was 18-20 inches long. Mine was still little when I gave it away, (it looked like it was going to be P.cichlid food if i kept it).
yeah that is fine, while capable of getting 30" I have never seen anything close to it and they grow reallllly slow so go for it, don't keep them with small fish though that could be a bad thing unless they are feeders...
Yeah I think it would be fine for quite awhyle as they are slow growers. At this fish store there was a 10" one and when the person tried to catch it, it tried to attack her then it jumped on the floor and started to slither away heh.
It would never really outgrow the tank, since it's rare for them to get to their maximum size in an aquarium environment. They're also less active than many fish and don't do a lot of constant swimming, so no need to upgrade your tank.
I have one in a 100g for its whole life with me(about 6month) and i got him a 8inch and he has grown to 9 1/2inch. so the grow slowwwwwwwwwwww even in a big tank. I see mine at the top of the tank when i thorugh in freeze dried blood worms but that is about it
The way they move and the way they grow if you start today with a 10"er it will out grow your tank, hmmmm, lets see, right about the time Canada gets it's own Disneyworld. Ya got a while.