Hello!
Some of the predator mites take care of other insects too, like whiteflies and thrips.
I was having a spider mite outbreak on my tomato plants, and just released a mix of three species of predator mites about two weeks ago, and they seem to b e doing the job. The plants have actually started growing quite a bit, and are flowering again.....So I think I can vouch for the mites too.
I know you are looking for aphid control, and here in the U.S., a lot of people use ladybugs. They usually show up on their own when i have an infestation, as my systems are outdoors. But, they can also leave whenever they want. They usually stick around though, and eat the aphids. if you are growing in a greenhouse, they are more contained, and will likely stick around longer. Perhaps you can locate a vendor, or find some locally. I'm not sure if you have ladybugs there.
When the ladybugs aren't around, I usually squish aphids with my fingers. I smear them around abit. I once read that the scent of dead insects keeps insects away. I don't know if it's true or not....but, it's totally fish safe pest control!
If there are any growers of certified organic crops there, maybe for export, they might be a contact that could point you in the right direction.