Would bicolor bleeny be a good choice for algea eating fish for 20 g tank,
are they agressive?! have 2 pepermint shrimp,3 hermits,fire fish,and
2 blue demsels.
Ecsenius bicolor ( Bicolor Blenny) would be a great choice for that size tank as they are peaceful, unfortunately I'm not sure what you mean by Blue Damsel as many species are called this and some can be aggressive especially in a small tank.
I would watch any damsel added to a nano. They can be little devils, especialy as they get older, and pick a fight with any and every fish in your tank.
I've had two bi-color blennies and they didn't really do much in the way of algae control. They have great personalities and I would totally recommend them for a nano... just don't get pissed at him if he doesn't clean up your tank.
update:this guy eats algea only,he is constantly nipping algea of rocks.I
give him some pellets too.
annyone noticed that the change colour(at night he turns greenish with
white stripes on head and mouth,and white leopard patern all over.