Had my tank for just over a year, with no real problems. Stocked with silver shark, couple of angel , tiger barb, red tailed shark, a plec, siamese fighter neons and zebra danions.
about a month ago i i got another red tailed shark plec and another silver shark. Within a week i noticed the new plec had gone missing it was about 2 inch long. then tonight red taied shark big plec and siamese had all been nibbled and saw the bigger silver shark eating a zebra danion. The size of the silver shark is about 3-4 inches. do you think he is the problem now he has a companion

?