They are aquatic invertebrates that live in sedentary colonies. Bryozoans live in tropical waters, polar waters and oceanic trenches. They have a crown of tentacles called lophophores that are used as feeding structures. They are classified into – 

  • Stenolaemata – Marine bryozoans
  • Phylactolaemata – Freshwater bryozoans
  • Gymnolaemata – Mostly-marine bryozoans

Only one genus of bryozoan is solitary (Monobryozoon) while others are colonial. A single animal in the colony is termed a zooid. Each zooid helps in producing a mineralised exoskeleton. 


Corals belong to the phylum Cnidaria and class Anthozoa. They are marine invertebrates that build reefs. They are of various shapes, colours and sizes. The colour of the corals depends on the dinoflagellates called zooxanthellae. These dinoflagellates live in symbiotic association with the corals. Most corals have an exoskeleton made of calcium carbonate. Some do not have a hard exoskeleton and are termed soft corals. They also have tentacles similar to bryozoans. Their tentacles have nematocysts or stinging cells. They can be both hermaphroditic and gonochoristic (unisexual).  Also Read: Phylum Coelenterata 

Difference between Bryozoans and Corals 



They are aquatic invertebrates under the phylum Bryozoa.  They are marine invertebrates under the phylum Cnidaria. 
They can be seen in freshwater, marine or sometimes even in brackish water habitats.  They are strictly marine organisms. 
They have tentacles called lophophores without the stinging cells.  They have tentacles with nematocyst or stinging cells. 
The building unit of a bryozoan colony is usually termed a zooid.  The building unit of a coral colony is usually termed a polyp. 
They are hermaphrodites.  They can be both hermaphroditic and gonochoristic (unisexual). 
Bryozoans are complex and advanced corals with a mouth and anus.  They are simple structures with a single opening that serves as both anus and mouth. 

Explore: Difference between Polyp and Medusa 

Frequently Asked Questions on Difference between Bryozoans and Corals


What are Entoprocta?

It is a phylum of sessile aquatic organisms that superficially resembles bryozoans. The anus and mouth of the Entoprocta lie inside the crown of the tentacles. Whereas in Ectoprocta or bryozoans, the anus lies outside the crown.


What are zooids?

It is a single unit or animal that forms a part of a colony. Some zooids share a common mineralised exoskeleton as in bryozoans. The zooid units can also be directly connected by tissues, as in Ectoprocta and corals.


What are coral reefs?

A long chain of coral colonies held together by calcium carbonate is termed a coral reef. The reefs grow best in shallow and warm waters. They provide shelter for most marine organisms.

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