So i get out of work in 2 hours, hoping when i get home the convicts not dead. You think if i take some media and put it in a fresh new 20 gallon he could stay in there for maybe a week or two until i get another tank? Like i said i do have a very large tank but dont trust him with the fish that are in there. So it seems this is the only option
Just got home and am watching them. This GT is like on a rampage ive never seen this out of him before he is literally ripping fins off the convinct and spitting them out leaving him terrified in a corner. i currently have the 20 settup. Added prime & am running a filter on it. Going to do everything you say because i will not even slightly believe this convict will be alive in the morning. Now am in another problem, my spare heater for this 20 gallon does not work anymore and cant get another on until tomorrow morning. Whats your suggestion?Looks like the terror is about 3"? It would be fine in the 20 for a couple weeks, couple months even, as long as a larger tank is in the immediate future. As long as the filter on the other tank is well established, just take some media out and put it in the new filter, at the same time as the fish is added.
Yes completely my mistake, you would think since ive been running tanks for a few years id know to do research before i grab a fish (Which i always do) this occasion was just spontaneous. i have the 30 gallon, a 125 gallon with a 6" asian redtailed catfish who also has a custom built 225-250 gallon waiting for him.Add a gallon or so from the 30 to the 20 long as well as some gravel, and the media. Don't add him to the the tank with the cat #nevertrustacatfish. Also everything Gourami said is 100% on point, terrors get up to a foot, your going to need a larger space for em.

is there any way to physically put the media in the filter?
It will speed up the growth inside your filter where you want it to grow.
The media will most likely do its job outside the filter but wont help much to seed your new filter