I think from my meagre fish experience
that the most freindly fishes Ive come
across are corys tetra and discus ...
the discus mainly only show aggression
to each other... on the other end some
of the more aggressive fish ive seen are
the gouramis and bumble bee chiclid of
course the larger the fish the more of a
chance of bitting and fin nipping to the smaller.
its important to try and get fish of the same size
and strength or finding which fish are freindly
with what. for instance i have tetra in with my discus
tank and theres no problem, now if i had tetra in
my oscar tank they would all be goners well hope you
choose well and try to do some research before hand
Aquria Central is a great source of information on what
fish are super freindly
