Someone in my tank is killing all my male guppies and female bettas. Tank is 15 gallon. Inhabitants are 1 female juv pearl gourami 1 juv angelfish 1 female betta(only one left out of 5) 1m 1f platy 1m 1f platy swordtail hybrid Around 10 female guppies. Moved my 5 male guppies to a 4 gallon tank temporarily(no heater). I even see my female guppies picking on my betta. Can anyone tell me who could be the culprit?