I have a handful of otocinclus, a snowball pleco, and a twig catfish. I’d like to grow some algae for them on a rock in a separate tank and then put it in their tank for them to eat. Is this a good idea, and if so any advice? I think I saw that you can put a rock in water with liquid plant food and set it in sunlight. Should I use a certain kind of rock? Or perhaps driftwood?