Juvenile Semi-circle Angelfish

Angelfish are highly territorial and have no affiliation with their young. So to allow the juveniles to remain in the adult's territory, for protection and food availability, they have evolved to be a completely different colouration. The adults do not see them as competition and do not drive them out the safe zone until they are old enough to fend for themselves and they start to change to adult colouration!

Awesome Photo!