Hello, I have a Fluval Evo 13.5 stocked with a pair of clownfish that are about 3 inches each. My clean up crew consists of a tuxedo urchin and 3 blue legged hermit crabs. This tank also has lps and soft coral and a BTA. I’m looking to add a third fish like a blenny or a goby. I have a decent amount worms so is it possible to fit one of their predators in this tank? If not, which fish could I add? I’m also looking to get a detritus eating invert to eat any leftover food and fish poop. I’m thinking of either getting a strawberry/tiger conch or a cleaner shrimp. My main concern with the shrimp is that it might hurt my coral during their feeding and my main concern with the conch is that it might starve. I don’t know if my urchin is all good with food because I don’t have any algae growing on rocks and I only have some pretty stubborn algae on the glass. I’d rather have the conch over the shrimp though since it’ll help keep the sand bed clean.