All of my fish pretty much only swim at the top level of the tank besides my pleco which is about 7.5 inches and sometimes hangs on the bottom. I've always had a fascination with inverts/critters and would like to have one. I have a 40g hex front so its decently tall for its size and I doubt It will be harassing my giant danios at the top. I have good cover and hiding spots for 1 or more guys on the bottom. My question is what combination of 2,3 or maybe even 4 (though thats probably too much) of a small crab/adf/rope fish/eel/shrimp or other things of the like that I haven't mentioned would go well together? I'm not against taking risks. Will my pleco bothered. I appreciate the input.