livestock suggestions

I want to get a lawnmower Blenny bc they’re cool as **** and I got some algae he could def take care of The watchmen goby’s pretty small still while the Blenny would be bigger the tanks only 13.5 gallon and I definitely don’t want them to hurt each other or be uncomfortable so what do y’all think

Hello! I'm loving the hobby and I feel that I'm actually getting a grip on handling it. I started my tank in February 2021, so I'm just about a year from cycling. I'm addicted and want the best for my tank. I have a 20g long reef tank with about 14 coral frags, two clownfish, lawnmower blenny...