I have two dominos in a 25 gallon peninsula tank and today I just realized one is dead twirling in the water column. I put them both in at the same time during 2nd week of cycling the tank. So ones dead and other is alive obviously and it’s been cycling for a good 4 weeks with them in there so idk if the water parameters killed one off or the other one just bullied it till it died. But all damsels are aggressive