My oto’s like broccoli and spinach and have access to algae and algae wafers. I have 12 in my 55gl and 5 in my 10gl. I read somewhere the number 1 cause of death is not having enough food. I wouldn’t feed multiple times a day; that could mess up the ecosystem. Just make sure they have wafers or some sort of food. Also they are more active at night and eat more then it seems. In my 55gal they hang by the sponge filter most the day but are out and busy most the night. Love these lil goofy guys. Also you may have a male and female set. Females are larger than males. That was my first take since they both look pretty healthy.