Well your larger fish haven't caused any problems thus far, only ones I'd be worried about is the curu and maybe dorado. This is just my experience with a past wolf that I'll share, it was a 12" mala, before I got him I had a pair of convicts both about 4" TL, my mala never bothered them but did eat feeders, so I got a pair of jewel cichlids cause I was still into cichlids and they were decent looking, the female was small but the male was the size of the convicts maybe a little longer, I skipped feeding one day and my mala ate them. My point is that it's possible they recognize fish as tankmate and as meal. So since you're adding the aimara after him he may look at it different than he looks at your small mala. A tip from my past experience and even the one curu I have now who has eaten or tried to eat many tankmates, when having a smaller tankmate you're worried about make sure the wolves are always full by doing daily feeding, in turn the aimara may grow faster and be safe including the smaller mala as well. But remember keep up with water quality, you have hardy fish but making them stress won't help them grow.