My 1 year old indie (Cheeku) has turned aggressive towards my 4years old golden retriver(Sherlock) Cheeku is attacking sherlock every now and than whenever he sees sherlock within his sight. I am trying to train cheeku, and give him small punishment like isolating him for while after the episodes of grawling and attacking but he keeps on crying and becomes too pushy to let him be in his way,I saty in flat amd the neighbours are not happy about the noises and hawling. Please help me understand how i can solve this issue, its becoming very difficult to keep them under one roof.