I wouldn't add another Goldie to that 20 gal
, I wouldn't add anything to that 20 gal
... That tank is minimal for a adult Goldie, IMO
Goldies need atleast 15-20 gal
per fish and I know alot of folks that say a Goldie needs atleast 50 gal
As for filtration, I agree with the AC300 (I believe they now list as AC30), and with the new Bio-max media Hagen/AC
is using they are even better Bio-Filters than they were before. I also put Chem-Stars in my two AC500's and have modified them with Bio-wheels for my 75 gal
Oscar/Plec tank... AC500's on steriods 8O !!!
The AC300 and other similar HOB
power filters have quite a output (create alot of current) and you'll want to mount as far to one side as possible so as to make a dead spot for your Goldie to rest in, that or break up the out flow with a screen of plants/structure.