I had to rehome a Danio. He was about the size of 2 red eye tetras together. He did well for the first week but then became rather aggressive. HE tryed to school with the tetra's but when one stepped out of line he made sure he chased them ALL over until they began to hide in the plants. He would pick and kill anything larger than him. WELL NOW HE IS GONE!!!!( a friend took him) And the tetra's are so HAPPY!! I have a 55 gal
with 4 red eye tetras, 2 corys, 1 kuhli loach and 1 beta. I have a lightly planted tank. When I get some extra $$ I will restock tank. But for now its a happy happy tank.