Trying to make low-stress fishing apparatus. Advice?

Barbless hooks sound good in theory, but they arent very efficient on fish like perch that thrash around a lot when hooked. To have success you need to be fishing very shallow, and be prepared to snatch the fish out of the water as soon as it bites - which brings it own set of risks to the table, like flopping off in mid air and hitting the ground before you can get a handle on it.

Imo you're better off using a barbed hook that will securely hold the fish until you can land it safely. More often than not, damage to the fish occurs by careless removal of the hook. This can be minimized by using a little attention and finesse - and needle nosed pliers instead of your fingers!

As for not hooking the fish through the gill or eye, it's going to happen sometimes and there's nothing you can do about it. But in my experience it's best to not have a hook that is too big or too small. Very small hooks tend to be harder to remove without further damage. Too large a hook is more likely to penetrate an area that you dont want, due to the large radius.

As for unhooking in a bucket of water, it's more important to secure the fish well rather than worrying about it being out of the water. If the fish is big enough, hold it by the bottom lip and use pliers to gently work the hook out. If the fish is too small to hold by the mouth, make sure to wet your hand before holding the fishes body. This will minimize any slime coat damage. Being out of the water long enough to do that wont hurt the fish at all. It will be far less risk than having the fish loose in a bucket where it can thrash around.

They live in water that's about up to my eyes... So slightly under 5 feet deep in the shallow parts. Too deep for a net.
I know these guys don't thrash if you hook them... I've seen them caught when people are fishing. They just race away, and if that doesn't work, they dash backwards and forwards.
Wouldn't a barbless hook be better for a foulhooked fish because it would just slide out instead of causing more damage? I one saw someone foulhook a big green sunny in the eye... When he tried to get the hook out, the whole eye came with it. Poor fish.

What sort of lure is good for assorted smallish predator fish like sunnies? Something rubber that looks like a grub?

As per the bucket thing, I'm not going to try to unhook something that's loose and racing around. I've removed them from hooks before, when this family had several kids fishing at once and their dad was busy with one fish at a time. They're all small enough to hold in one hand, so I held them in the water and just moved the hook out.
Why would pliers be better for getting a hook out? Wouldn't they make it harder to feel what you were doing?

I'm trying to directly identify some things in one spot, but I want to be able to do it whenever I want. I'm keeping track of the river, and also I'm checking for tilapia. I found a dead tilapia near there once.

A cast net is worth a try, you'll get everything with minimal damage, not just sunnies and perches. Also use a small hook with a live earthwork. This allows for a more precise hook up with the fish. Most foul hooks are from a fish attacking a lure and missing or the fisherman setting the hook into the face or body on accident due to quick movements of the fish. Live bait allows them to swallow it and hopefully get the hook in the mouth. Hate to break it to you, but anytime you cast a hook in the water you should expect the worst. Fish long enough and you'll find yourself sitting on a river bank with a bleeding dying fish in your hands struggling with a deeply lodged hook. It comes with the territory, nothing about fishing is humane. If you just want to find out whats in there contact a university or local group like the person above said. If you fish, you might not like what happens.

A seine net isn't an option at the moment, unfortunately. That would be neat to try, though... Wonder what I could get doing that. I bet there's catfish.
Do those sorts of nets work if the water has random boulders all over the bottom?

Ooh, I hadn't thought of the rag. That would help.
I don't think I'll have to worry about teeth, but I'll bring some needle-nose pliers just in case.

Circular, barbless hooks
Soft clean rag for gripping
Land quickly
Needle-nose pliers
Remove hook quickly
Any other tips?