A water trough is not a suitable environment for fish keeping. Goldfish are the most likely to survive, but as SR pointed out they will contribute to algae growth rather than hinder it. Fish geared towards algae control are going to be tropical in nature and not suited to living in a trough.
Really, fish are not a great addition to the tank. The problems they will bring with them will lead to more upkeep of your tank rather than less - it will be easier just to perform regular routine care of the trough by draining, scrubbing and filling more frequently in the summer months -which may mean using multiple smaller water containers if the larger single unit is going to be too much hassle to do so.