I have a 150 with a 14 inch aro 6 inch Oscar and 2 parrots. I used to have two other blood parrot however my Oscar is the main aggressor in the tank. It used to bully my Arowana and would hip his fins and tear them however my Arowana grew some balls and the Oscar doesn’t try him anymore. My two other blood parrots both died of stress related problems the first that died I came home and he was floating on the surface. I did a water test and everything was normal but I still did a water change. I don’t think it has anything to do with the later as my parrot routinely lay eggs and the aro is more sensitive to water parameters than the parrots. The other parrot that died was the male in the bonded pair and I saw it having swim bladder issues suddenly. He was being pushed around by the Oscar and other parrots. I scooped him out and put him in a medicated bin with meth blue and salt and plenty of oxygenation. He was floating belly up on the surface and couldn’t be saved and died when I woke up in the morning. My Oscar since he was 2 inches had always been super aggressive and would batter any fish in the tank. The remaining two parrots is the female who’s around 3-4 inches and the runt of the litter this small deformed male who’s smaller than the rest. I’m scared that the male will be the next one to die as it’s small and always sits next to the filter intake for cover sometimes in weird dead looking positions. I dont have much more room in my house but I have a 70 gallon tub for my two turtles both of them are non aggressive and the biggest one is 4 inches. That tub has plenty of cover and houses a large school of guppies and two catfish as well. I could put the runt in there to grow out or I could get another tub with his own heater and filter of a smaller size and put him in there for a while to grow him out. He hasn’t really grown much as he can’t compete with the larger fish and his mouth is deformed so it’s hard for him to eat. If it was just him in a tub I could feed him multiple times a day with frequent water changes to help him grow faster. I want to add fake plants or other forms of structure to stop LOS so the Oscar would chill out. I used to have two large Amazon swords that were beautiful and worked well but I glued them to rocks and the oscar started ripping them apart and uprooting them and they all died now the only forms of structure are a big log in the center of the tank with a cave that the Oscar can’t enter and the filter pipe which they use. I want to add fake plants to the tank and other forms of obstruction but they have to be safe for the Arowana I don’t want him jumping onto it and dashing into it and hurting himself. Something like large fake plants I believe would work. Any other suggestions?