Can anyone recommend a small fish for my 20L frag tank? I will have one big piece of live rock in there with smaller pieces laid around, as much egg crate as I can fit and it will be bottomless....

Dont really care if it's the ugliest fish out there, just looking for a work horse to help with any algae that may pop up....

Might have a six line in there to help with any pests but unsure of that yet..