No, a 20 gallon is not big enough for the bala, red-tailed shark, or pleco. Balas really need shoals, and reach a foot long, so I'd recommend no less than 125 (and that's a little small.) The RTS will reach about 8", so I'd say at least a 55. The pleco, if it's a common (which it probably is) will probably reach well over a foot. Few people have aquariums sizeable enough to keep full-grown common plecos. I would suggest returning all of these fish to a local fish store (LFS) Most good LFS are okay with taking unwanted fish off of your hands (some do it for store credit!) There are plenty of options for a 20 gallon
__________________
current setup:
5.5 gallon low-light planted tank
-nothing....thinking a mini-community.
for reference: my name is Julie
