Lily wrote:
1. 20cm i think but they are adults
2. length 6ft depth 1.5ft width1.5
3. 1 bubble corner filter , 1 jet filter
4. Don't have tester
welcome aboard....
so you bought a decent size oscars, not one but two.. 8 inches long (20 cm)
might be adult already. bullying may be part of territorial supremacy or courting.
your tank is big enough for the two and since they are both new to the tank, they
should be still exploring the new home...should not be fighting yet.
my theory is..yo have two males, thus, they will keep on fighting.
just my two cents evluation.