The tat is doing worse and worse and is getting pieces of its tail bitten out (already lost an eye), although it's not missing any scales nor does it have any other body damage, including missing scales. 
It still won't eat anything but live and is looking really skinny. Do you think I should just start feeding it live more so it gets in good condition and then start to try to get it to eat other things or should I move it?
The problem with moving it is to where? I need to move the jar, flagtail and tinfoil barbs out of the 20 gallon into a 55 that I just got rid of all the inhabitants of (minus a beat up Petsmart "Trimac" that's in a divided partition, but it can be moved). I was going to move the trimac into the 20g and use it as a quarantine tank, but I'm thinking I'm going to need to set up my 55 instead, but I don't really want to as I was going to sell it and would need to buy more filters. Would it be safe for the tat in the 55 w/ the jar, etc. or should I do something different (I know i'm screwed if the jardini turns mean)?
PLZ HELP!

It still won't eat anything but live and is looking really skinny. Do you think I should just start feeding it live more so it gets in good condition and then start to try to get it to eat other things or should I move it?
The problem with moving it is to where? I need to move the jar, flagtail and tinfoil barbs out of the 20 gallon into a 55 that I just got rid of all the inhabitants of (minus a beat up Petsmart "Trimac" that's in a divided partition, but it can be moved). I was going to move the trimac into the 20g and use it as a quarantine tank, but I'm thinking I'm going to need to set up my 55 instead, but I don't really want to as I was going to sell it and would need to buy more filters. Would it be safe for the tat in the 55 w/ the jar, etc. or should I do something different (I know i'm screwed if the jardini turns mean)?
PLZ HELP!