None of them eat my GSA or fuzz algae on leaves I usually just have to cut off all the 'fuzzed' leaves luckily there aren't that many and they all were from a deficiency in the tank which I have corrected.
I, too, like and have used red ramshorns effectively. Unfortunately or fortunately (depending upon if you’re a ramshorn in my tank), they all died out for lack of food. For algae on plants, I have found a way to utilize Oto’s and true SAE’s. They seem to like dead algae species that they wouldn’t normally touch when the algae is alive. The trick is killing this algae without killing the fish or going through the troublesome spot-treatment methods.
To do this, I create an isolation room inside the tank, with an inverted clear container covering sections of plants, and having high circulation from a cheap little pump (wand and strainer removed from this little internal filter). Into this contained section of swirling water, I inject 7 ml / gallon of H2O2 with a commercial syringe and allow it to circulate for an hour. The opening of this ‘cone’ sits on the substrate and covers whichever section of the tank that I choose. After the hour, any non-decomposed H2O2 is diluted harmlessly into the rest of the tank when I remove the cone. Doing this protects the fauna from the effects of the H2O2 (and I have killed many a fish with H2O2 in years past).
The container I use has a 7” x 7” opening and is 9” high, but you can choose any size that you want for your tank. It will float (if it’s plastic), so it will have to be weighed down. I use four, 3.5 oz, fishing tackle weights. The syringe will also float out of the hole, so I cover the hole with one of the weights when I remove the syringe. No need to worry about H2O2 escaping through this hole, since the hole is too small to cause a significant loss.