I have an angry dwarf gourami that harasses any fish he sees. Are they really this aggressive? or is there something causing him to do this? i have him in a clean 10g with 4 danios and 4 ghost shrimp, he harrased my two guppies to death and also 4 shrimp and 3 danios have gone missing. Im pretty sure he is the culprit since he chases anything that moves. What can i do?