mine act the same way sometimes. as for the food, keep putting it in the SAME place each night after you turn off the lights and take it out in the morning and they should eventually notice. mine took a few days to notice it, but now they really like cucumber (which i usually leave raw). I usually feed them cucumber of a algae wafer 1x per week.
also, my tank doesn't really have any noticeable algae, but their bellies stay plump so i think they must be finding some algae on a rock sculpture i have.
Eventually, it did take two days for my otos to notice the zucchini (placed at one and the same spot). I saw all three of them eating from it for a while, but not too much. Maybe they are not really that hungry (plenty of algae) but are rather getting used to their new environment.
That frantic behavior stopped in a couple of days. They got a lot calmer and continued grazing on algae. They do however go back to being just crazy chaotic swimmers ala oto style from time to time. They literally freak me out sometimes because they behave as if they are having a panic attack or something. At times I can even hear it when they bump their noses into the tank walls while swimming at high speed.
I have noticed them hide from the light when it gets dark outside. The tank lights are on till 10pm normally, but at dusk (around 8.30) they gather and look for a shady place to stay as if waiting for a threat to go away.
Could be they need better hiding from the light. Now that I've moved to a fairly high light setup, I never see my otos when the lights are on. Not even under the leaves of plants. They are hidden under solid objects (wood, rocks, cave, etc) until the light are off. They are out and about during the day when the grow lights are off.
When the lights come on, they swim quickly for cover.
Yes, they definitely like hiding from intense light behind solid objects. Mine hide behind the filter, air stone and rocks. I have a few background plants but unfortunately I had to trim them severely because they started falling apart due to excessive diatoms growth.
Mine LOVE repashy solient green. They also like zucchini and in a pinch will even eat kens veggie sticks. I put the food in the same place every time and now they sit there and wait for it. I feed them ever other day because they keep the tank so clean.
My daughter has 6 otos in her tank. They don't mind intense light and love the zucc. we place for them. You can watch them all day. They poop tremendously if well fed I've noticed. If you have small plecos, is the same sort of feces.
As far as swimming frantically around the tank at high speed, I've always read that it's typical oto behavior. Mine all do it every once in awhile. On the subject of feeding, when I first set up my tank (after they'd decimated the diatoms) I started putting in a slice of zucchini in a clip once a week. It took them a few weeks to start going for it, but now that they have they'll go for it any time I put it in. I just rinse it under water and put it in raw. I found the light shyness curious too, my otos have no problem with light.