Aqadvisor.com is a great site to check stocking levels though it's more of a guideline than an absolute rule. You can get a pleco if you want, just get a bristlenose pleco (Ancistrus sp.) and not a regular one. They only get to 3ish inches and are really cute! For stocking you could do 12-15 smaller schooling fish (maybe 5 endlers, 5 neons, 5 rummynose?) and 7-10 habrosus or pygmy corys no problem. Good luck!