Well, my first advice to you would not to get a redtailed shark as they get relatively large and get more aggresive as they get bigger. Also, the pl*co is gonna be a waste factory! So maybe thing about getting a smaller, perhaps dwarf species of pl*co like bristlenose or something! They come in so many variety of colors it amazing! You could replace the redtailed shark with some SAE(Siamese Algae Eaters), they are great, remain peaceful as they grow, and are wicked when it comes to cleaning up the algae! Only down side is that its a pain to find the real SAE's, most pet stores mislabel fish as SAE's. If you know what you are looking for though it is very rewarding. Mainly look for the horizontal lateral line that extends into the fork of the caudual fin. Also they only have one set of barbels instead of two like most other algae eaters. Next i would get some tetras. Serpae, Broken Stripe, Congo, and Black Skirts are some of my fav. Add spice and color to any tank. Scissortail Rasboras are another awesome option if you like the 'clear' fish look. Experiment with various species. Gouramis are an excellent community fish, although get more than one because if there is only one they will become aggresive and pick on some of the other fish. Either get several of the same type or mix it up! If you want some odd ball fish get some glass cats. They are beautiful, amazingl, and in a catagory all their own! They stay relatively small and peaceful as well! Thats just a few options...there are, of course, hunders of thousands of possibilities out there so research and explore! Enjoy!