A symbiotic Relationship

Unique Symbiotic Relationships

It seems like every beginner aquarists’ dream nowadays. They set up the tank, cycle it, and want a pair of clownfish to start out with that they can eventually introduce an anemone to. Many time, the clowns don’t recognize their new home and refuse to be hosted by the anemone addition, leaving their owners confused, frustrated, and often disappointed. Wanting a symbiotic relationship in their tanks, a lot of people turn to goby and pistol shrimp pairs next and completely forget about other relationship-forming reef inverts. Aside from the occasional grumpy pistol shrimp that decides to rebel and eat a few snails or tank mates, this symbiotic relationship is typically much more successful than the clownfish and anemone trials. But, what if you want something more unique, even exotic? Some other pairings are quite easy to establish in tanks, and these mutualisms can encourage strange or interesting behaviors that we wouldn’t see otherwise.

Anemone Crabs and Anemones

Anemone Crabs are small white and brown crabs that aren’t aggressive towards anyone unless protecting their territory. Even then, they are more likely to flee than to fight. Because of this, I think these little guys are great additions to every tank with anemones. Cleaning their host and filter feeding with their fans provides them with enough food. I have kept them with Bubble Tips, Long Tentacles, Maxi Mini Carpets, and Rock Flowers. The anemone provides food, shelter, and some protection to this symbiotic relationship while the crab provides a cleaning service and defends against predators who try to harm their host. Both benefit from this relationship, and it can be very interesting to watch!New blog post (%TITLE%) has been published on The Algae Lab – %URL%

Anemone Shrimp with Anemones and Cucumbers

The White Spotted Anemone Shrimp is a small, mostly transparent shrimp with white spots on the body and orange marks on their tail. They coat themselves in mucus from their host anemone that makes them immune to their stings. If an anemone isn’t available, they will oftentimes be hosted by sea cucumbers, mushrooms, or other corals. Sharing meals with their host, they provide a cleaning service and protection and receive protection from shrimp eating fish in return (much like Anemone Crabs).

Damsels and Anemones or Corals

Believe it or not, a few damsel species will also accept host anemones. Specifically, Domino Damsels are the most likely to be hosted, but many report Three Stripes also take residence in their anemones. These two species tend to prefer Bubble Tip Anemones, but also take to Carpet, Magnificent, and Long Tentacle Anemones. Yellowtail, Azure, and the previously mentioned damsels (and others) can also be hosted by coral itself. Most commonly, they are found in Pocillopora, Montipora, Acropora, and other SPS corals. Studies have also shown that this symbiotic relationship increases the photosynthetic rates of the host, among other benefits. So, these little fish can be great additions to SPS heavy reef tanks!

Bangaii Cardinals with Long Spine Urchins

In the wild, baby cardinalfish fall prey to numerous predators. To combat this, they have developed a relationship with Long Spine Urchins. After the young leave their father’s mouth, many will find Long Spine Urchins and hide among the sharp spines, out of reach from predators. Their black stripes help them blend in with the urchin, and sharp venomous spines keep predators away. This fish is very easy to breed in home aquariums, and adding one of these urchins can add a new, exciting element to the mix! In addition to providing refuge for fry, this great reef invert will help keep your tank clean of unwanted algae. I have even witnessed adult Bangaiis attempting to live within the spikes of these urchins in the home aquarium.

Pom Pom Crabs and Their Anemones

Pom Pom Crabs are small crustaceans that are pink, white, and tan in color. Their bodies almost look like a stained glass window, as they have patches of different colors outlined in black all over their carapace. In each front claw, the crab carries a small anemone. In doing so, the crab can use the anemones to capture tiny prey, pick up food particles, and defend itself from predators by stinging them. In turn, the anemone receives little bits of food, and may be propagated by the crab. If no anemone is available, the crab may use coral polyps or sponges in their place until their natural partner can be found.

Hermit Crabs and Anemones

A few species of larger hermit crabs in the Dardanus genus have developed symbiotic relationships with anemones. Camouflage, protection from predators, and food sharing are all benefits the crab receives, and the anemone gets food and transportation. When the hermit outgrows its shell, they either leave the anemone on the old shell for another crab to use, or transfer them to their new shell. The one drawback to this pair is that they are not reef safe, and the hermits are aggressive. But, they can make beautiful additions to the clean up crew of larger predator tanks!

Trapezia Crabs with SPS

Trapezia Crabs are small and vary in color tremendously, ranging from purple to red to white to polka dotted. Unfortunately, I have witnessed many killed by reefers who dip their coral in iodine before inspecting, or simply rip them out of their hosts assuming they are evil coral eaters. On the contrary, these little crabs are absolutely wonderful additions to any reef with branching SPS corals. Typically, the are found in Procillopora or Acropora corals, but will also thrive in other branching sticks. Crawling throughout the coral colony, they aid in proper water circulation within the coral and provide extensive cleaning services, along with warding off predators. In turn, the crab receives food from its host and protection from crab-hungry fish. I have seen a huge Birdsnest colony that was cleaned of all algae nearly overnight by one of these crabs, and its health quickly flourished. In comparison, the neighboring Birdsnest colony without an Acro Crab remained sparse, and grew bubble and hair algae along its base. For all of these reasons, I truly believe Trapezia Crabs are one of the best reef inverts available, and should be kept in every SPS reef tank!

No matter what kind of saltwater aquarium you have, there is some type of pairing symbiotic relationship that you can keep. Hobbyists try to mimic the natural ocean for their fish, and adding or completing one or more of the above groupings can easily benefit aquarium inhabitants and provide you with hours of entertainment!

63 thoughts on “Unique Symbiotic Relationships”

  1. I introduced an anemone to my tank with my clown fish. At first they ignored the anemone, until I caught them and put them together in a small acclimation box for a few days. Within a week they hosted the anemone.

  2. I got to have one of those pom pom crabs, I used to have one but it vanished and I never saw it again. Super tiny little guys

  3. Buddy Blankenship

    Cardinals and urchin. I have the urchin but no cardinals. I have a pair of clarkii clownfish that just brutalize my bubble tip anemone.

  4. Im still waiting for my clowns to figure out my BTA. I do have a pistol shrimp and orange spotted goby though to watch their symbiotic relationship

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