What Have I Done!

[m00ms]

hi all,
 
my tank is a 200 lt mature tank and all was well but i am drawn to bottom feeders so mid/top of tank looked bare so i brought 8 columbian tetras to fill the empty space.
 
all thats happened is the 8 tetras are hiding under drift wood and rest of my tank mates are picking up on there nerves and they are all acting scared.
 
my tank mates are 4 panda garra,7 cories,2 bolivians.i have only had the columbians since saturday afternoon so will they settle down and calm tank down again or have i made wrong choice with them as mid fish?

 

[attibones]

Check your water stats. Because you'd added eight fish after, presumably, having the tank stocked as it is for a while, your bacteria culture may not be prepared enough to really handle the extra ammonia yet. Check you ammonia and nitrite. Go ahead and do a water change. Your other fish are all relatively peaceful species, though I've never worked with panda garra (but a quick check on seriously fish says that they are peaceful when stocked with three or four, as you have). 
 
It may also help if you can rearrange any decor in the tank.