I have Zebra Oto’s thriving in 3 different tanks, and a few that look like they would spawn, if the tank was less crowded… I’ve found these guys really like soft driftwood, I also have a school of King Tiger Plecos in this particular tank, and the Oto’s spend as much time munching on the driftwood, as the Plecos do… I may have coined the word “Repashi sticks” but this tank doesn’t get any… the other 2 tanks that have the Zebras in regularly eat Repashi Soilient green , off of some 1 inch branches, that I trimmed to the right length…
BTW, I have several shrimp in this tank... you could try feeding in a couple of places to spread the food out ( don't over feed ) but if all the food isn't in the same place, it'll spread the consumers out, between spots... they may not segregate by species, but there may be more room for each???