The Plecos are lazy swimmers and tend to stay in one spot, more or less, depending on the algae growth and the food that the turts miss that falls to the habitat bottom. The Plecos skin is very hard and a small one would make a fair meal for a turtle. That's why I suggested a large specimen so a turt would not try to eat it. I also mentioned that the cost of a large Plecostomus would be high and how effective would one be in a large, say 50 gallon tank? I, personally, have never employed one for algae control. I've always used pennies, chemicals and/or plants, and this year am trying Black Trapdoor Snails in my outside pond. I use pennies and a bar of silver and copper for control in my 265 gallon basement pond, besides which, except for the 160 watt mercury vapor bulb that is on during the day, there is no sunlight or any light except what comes through the glass blocks that are used as a replacement for regular window glass. I would try the AlgaeFix first and when the algae is under control and even while the chemical is working, I'd drop a dozen pennies in there for continued control. OR, just go with the chemicals--faster and cheaper because so little is required for your size tank. George