Thanks for all the comments guys!
FWIW, the larger fish is forskahlii and the smaller is brevis. Those two species are probably tricker to tell apart than VATF and TATF. I feel as though I've got a good handle on it after looking at them in person, but I also feel that to tell them apart this small, I'd probably
have to see them in person.
I am very concerned about putting them in the big tank, though to be fair Max is the least of my concerns. Drogo the arowana is significantly larger than Max and was eyeballing the little tigers while I was floating them a little too closely lol. He is also more than big enough to eat the baby tigers, I have no doubt he could easily swallow them whole. Ginger the juruense catfish is in the same boat, I don't trust her either.
I don't
think Max would give me too much trouble, but I'm not sure enough about that to bet my money on it by putting the little guys in there with him. My plan at this point is to drop the water in Max's tank to about 74* over the course of a few weeks and to slow down on his feeding. Meanwhile, the little guys are going to be living in 84* water and will be undergoing pellet training. Hopefully Max's growth will slow down somewhat and the babies' growth will speed up and they will be able to close the gap some.
Max and the babies will also be drowned in dither fish, Max is getting a trio of similarly sized balas and another trio of similarly sized Tor. The babies have an Atlantic tarpon, a trio of tinfoils and hopefully soon they'll have a few more toothy friends. Hopefully they break to pellets soon. The FATF is an absolutely demonic thing who harasses the other babies relentlessly. That's not overly concerning to me however because Max behaved in exactly the same way when he was this size and was indeed likely even worse. I broke him so I'm confident of my ability to break this guy thanks to the lessons I've learned.
The new guys:
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Brevis: