Sorry, been away for the past few days.
(Limp Bizkit is on the radio........this time i'm goin to stand up and shout, i'm gonna do things my way, it's my way......my way or the highway) ;D
Kicka$$ song!
Ok, now back to the question...the severum isn't as active as when you first got it. It could be a variety of things, but my first thought would be stress. Severums can be shy when kept in a tank that is to small or one that doesn't have enough hiding places. A ten gallon hex doesn't really give all that much swimming room or provide a place to feel secure. That would be my first guess.
My second would be some sort of illness or definciency. Have you taken a good look at it? Anything out of the norm? Spots? Rashes?
I really think that if you got a larger tank he would be much happier. Full grown severums can get to about ten inches, so a 55 g will be more suitable to your fish.
Ryan, maybe try some dither fish. Some giant danios or something of the sort, small but large enough and quick enough that it won't get eaten. It could be that the Africans kept your firemouths busy and when you took the Africans out they got bored. Are there other fish in the tank with your firemouths? Adding a few fish will often coax shy fish out of hiding.
Hope this helps