I bought algae wafers for my pleco, but the first one I put in got devoured by my 4 rosy barbs and my 2 angels. The angels were a little intimidated by the barbs' feeding frenzy, but they managed to nose in. Anyway...is it okay for them to be eating those?
Yes it's fine and healthy for them too (see about 4 or 5 reply's down). However, it's not for them... it's for the pleco. So it looks like you will have to be a bit creative in getting it down to him. Usually once it's on the ground the other fish will have a hard time getting to it because of the location of their mouths. The first method used is night time feeding. Drop it down when it's dark in the tank since that's when the pleco is most active anyway, and see if the others leave it along. Another method is via distraction. You feed your flakes or whatever floating food you want the other fish to have on one side of the tank and then drop the wafer on the other so it hits bottom before the others notice it. If all of that fails then go to a hardware store and find a pvc pipe that had a large enough hole in it to allow the wafer to freely fall through it. Also make sure it's about 4" or so longer then your tank is deep. Wash the pipe as best as you can (inside and out) with hot water. Then put it into your tank where you want the wafer to sit. Then just drop the wafer into the pipe and it will drop out the other end on the bottom without any of the other fish even knowing it was there. Good Luck!
Another thing to try IF those other methods don't work out would be to break the wafer into pieces and hide them around the tank at night. I think you can also try slices of cucumber & zucchini for the pleco to eat.
I had questions about the same kind of thing. I bought algea wafers for my pleco, but the first few got eaten by my platys. The longer you put them in there, the less they care about them. After about a week, maybe a week and a half, my other fish stopped pecking at it and the pleco had a full meal!