can I put a catfish and an algea eater in my aquarium with a highfin and 3 glo fish?
What type of algae eater and what size aquarium?
Stay away from the chinese algae eaters, they are not very good community members and often end up feeding on tankmates prtotective slime coats.
Plecos are not the best idea if you have a small aquarium. Many of them can reach lengths of a foot or longer.
If you have algae growth, I would recommend a few snails.
What type of catfish? Something like cory cats are excellent choices. They stay small and like to be in groups of their own kind.