Would one of these guys be happy in a 20H tank? It seems like every sight says something different. The only other fish would be a true perc or a black occellaris.
Just hope your not planning on adding much else to the tank fishwise, and you should be ok (neon gobies etc would probably be ok). These little buggers can get quite mean.
even though this poll isnt very definitive, people seem to say that it could go either way. most, however, seem to say that they need somethign larger. id rather have a happy fish than one that isnt. i may go with a yellow-tail damsel instead as a third fish(if i get 3)
Back in the old days (like 15 years ago), I had a cherub in a 20g tall for about 3 years and it did fine. It was thriving when I tore down the tank. Just my two cents.
At the same time Len had his I had one also, in 29. It seemed fine to me at the time.
Right now I have a flameback angel, which I expect has somewhat similar habits. It eats prepared foods well, and I doubt it needs all that much grazing.