Drop eye should be preventable given the right food ( floating food) and the absence of fish below an arrowana….
When we had our large ones in college, they both had one eye drop on them. I blame it on having some catfish on the bottom that they always kept an eye on.
They are truly beautiful as they swim and I think with your 300g, adding some current makers would make them real happy.
If you want one that will work with a community, I’d recommend a black or a silver. The jardini is a voracious predator and anything that fits in its mouth will become dinner. Take my new 4-5” jardini…..it has grown in the few weeks I’ve had it about an inch already. It eats floating pellets, but as I type this, it has also eaten 10x 2-2.5” pearl danios. I am down to 1, and last night, I noticed that he was swimming lower in the tank, trying to size up my adult serpae tetras. I think they are ok, because they are a wee bit too tall to fit in his mouth.
I think you may also want to think about price….. silvers are the cheapest, and honestly the most graceful when they swim from side to side. Jardinis have really cool markings too, but they look like a hybrid between a standard fish and a silver arrowana, so they are super interesting too. I’ve never owned a black arrowana, but as adults, they look almost identical to the silvers to me, so they may not be worth the asking price.
