once your tank is cycled and ready for fish, which it is not yet, you could add a siamese algae eater to take care of algae.
weither or not it's a good ieda to add some loaches (almost all loaches need groups) or a catfsh depends on what loach/catfish you want. with well over 2,000 species fo loaches and vcatfish combined on earth, there is definely a loach/catfish species that you can keep.
oh, and whatever you do, DO NOT get a common pleco, pictus catfish, columbian shark, irridescent shark, clown loach, channel catfish or chinese algae eater! all these species of common bottom dwellers will outgrow your tank. always be sure to carefully reseach any fish you plan on purchasing. do not listen to your pet store when stocking your tank, always do your own research.