Commensalism

Commensialism means literally 'at table together'. This is a symbiotic relationship between two species in which one species benefits and the other neither benefits or harms. Often, the host species provides a home and/or transportation for the other species.

Examples:

• clownfishes live within the waving mass of tentacles of sea anemones; Because most fishes aviod the poisonous tentacles, the clownfishes are protected from predators. Perhaps this relationship borders on mutualism because the clownfishes actually may attract other fishes on which the anemone can feed. The sea anemone's tentacles quickly paralyze and seize other fishes as prey;

  Clownfishes are good exmaples of commensialism.

• epiphytes, e.g.some tropical orchids use trees or branches of trees for support without harm or benefit to the tree. The epiphyte obtains more light and air in this manner;
• the remora, a sucker-fish, lives in close association with sharks or other larger fish. The dorsal fin of the sucker-fish is modified to form a sucker; it uses this to attach itself to the shark; The sucker-fish is small and does not injure (or benefit) the shark, but envoys the shark's protection and lives on the scraps formed as the shark devours its prey;
• another example is the interaction between Ecklonia maxima and Patella compressa. The Patella gets it food from the plant, the Euklonia, which is not harmed or damaged in the process.

In the Western Cape of South Africa, you get Patella cochlear attached to Euklonia maxima.

Mutualism
Parasitism