The 'inch per gallon' guideline refers only to fish that reach an adult size of three inches or less.
It's not just about whether fish will 'fit' in your tank, stocking wise, it's also about making sure they have enough space to swim about. Technically, you could keep a single clown loach in a 100l tank (if you did enough water changes to stop it becoming stunted), but it would barely be able to turn around; no life for an active fish. They are also very, very social fish and it's really not fair to keep one on its one. The stress of being alone will cause it to be more prone to diseases, like whitespot.
I would also say that you're massively underestimating the size of your fish. When doing calculations like this, you must use the eventual, adult size of the fish, not the size they are now. So your four cardinals would be eight inches, not two, the embers five, not three and the panda cories six rather than four.
If your plec is a clown plec, he can stay though.
It's not just about whether fish will 'fit' in your tank, stocking wise, it's also about making sure they have enough space to swim about. Technically, you could keep a single clown loach in a 100l tank (if you did enough water changes to stop it becoming stunted), but it would barely be able to turn around; no life for an active fish. They are also very, very social fish and it's really not fair to keep one on its one. The stress of being alone will cause it to be more prone to diseases, like whitespot.
I would also say that you're massively underestimating the size of your fish. When doing calculations like this, you must use the eventual, adult size of the fish, not the size they are now. So your four cardinals would be eight inches, not two, the embers five, not three and the panda cories six rather than four.
If your plec is a clown plec, he can stay though.