THe BK fish will get very large bigger then the bala's and that size tank is too small for bala's for life.
With that being said My bala's swim back and forth all day long, and try to avoid the drift wood I have in the center of the tank. They stay mostly at the top of the tank, as long as the deco you have leaves the top half open they will be happy.
As far as filtration at least two canisters or a cansiter and like an ac110 would be needed. I just tried to cut down to only one cansister on my 55 gallon, and after 2 weeks + 6 new fish I have started to see 0.1 ammonia. I say 0.1 because even though the API test is yellow its not a dark yellow, like normal.
With that being said My bala's swim back and forth all day long, and try to avoid the drift wood I have in the center of the tank. They stay mostly at the top of the tank, as long as the deco you have leaves the top half open they will be happy.
As far as filtration at least two canisters or a cansiter and like an ac110 would be needed. I just tried to cut down to only one cansister on my 55 gallon, and after 2 weeks + 6 new fish I have started to see 0.1 ammonia. I say 0.1 because even though the API test is yellow its not a dark yellow, like normal.
