Hi, I have 2 Oto cats with me for about 8 months now and I have never ever seen them eat the Hikari veggies tablets I put in my tank. The tetras eat them so there is no waste. So, I guess they must have enough algae to sustain them and my tank is actually very clean especially when compared to before I got them. However, I do wonder what happens when there isn't enough algae around. I tried putting in cucumber bits and peas but the otos don't eat them. I wonder how I can tempt them to eat other food and what other vegetables I can try.