Cichlid Dithers+Algae Control

[insecurity]

Howdy. I have a 20gal with two Electric Yellow Cichlids- one male and one female. I have a filter (forget the brand) rated for 70gal, to ensure properly water quality.
My cichlids are doing quite well, but over than to eat, they don't come out of their caves that I've provided unless I'm standing in front of the tank.

I've read that some cichlids need dither fish to keep them active, and I was wondering what (or if) I should try a small group (no more than 3-4) of dithers for this.

As well, I'd LIKE to get a pleco for this tank, but I am concerned that my cichlids (esp. my male) will attack any pleco I put in. He goes nuts when I put the gravel vacuum in.

Any suggestions and/or comments are welcomed.

 

[Borderlesscott]

If you mean Labidochromis caeruleus, it's an African Cichlid and you wouldn't usually put dithers with African, American Cichlids tend to have dithers added. IMO 20g is also very small for a pair of Labidochromis caeruleus by themselves without a pleco.