Tag Archive: cnidaria

What’s going on?

Dear Backyard Zoologist readers,

You’ve probably noticed a huge drop off in posts recently and I wanted to let you know what’s going on. In all honesty, I began this blog over a year ago because I enjoy sharing information and pictures of awesome wildlife. I still do, but at the moment I have a lot of cool but time consuming things going on and creating these posts on a regular schedule is starting to become more of a chore than something I do for fun. So, I’ve decided to only write new posts when the spirit moves me instead of on a regular schedule, to eliminate the dreaded deadline of Monday and Friday. Still, I hope you’ll check in periodically to see what’s new or better yet, sign up for e-mail notifications to let you know when I do post something new.

I still have lots to share…for example, did you know that this animal:


A giant green Anemone. Image taken at Fitzgerald Marine Reserve tidepools in California.

is used as a vertebrate heart stimulant? Or that this animal:


A 9 banded armadillo. Image taken at the San Francisco Zoo.

always gives birth to identical quadruplets? And naturally grows the bacteria responsible for leprosy on its feet? Scientists couldn’t cultivate this bacteria in a lab, so they brought in live armadillos to collect the bacteria to work with.

Or that this animal:

tree shrew

A tree shrew. Image taken at the Oregon Zoo.

Is very smart and has a larger brain size to body mass than humans do?

Or that this animal:


California kingsnake, Kali, my personal companion.

Is called a kingsnake because it eats other snakes, including rattlesnakes and is immune to rattlesnake venom?

Or that these animals:

rock doves

Rock doves, a.k.a. pigeons. Image taken in San Francisco.

are one of the few birds that feed their young a type of milk?

Or that this animal:

marine toad

A marine toad. Image taken at the San Francisco Zoo.

is one of the only toads that will sometimes eat vegetation and dead things? While other frogs and toads want to eat only moving things, this toad is even attracted by dog and cat food left in yards.

Or that this animal:


A lionfish. Image taken at the California Academy of Sciences.

is covered in highly venomous barbs and that dolphins will sometimes grab these fish by their tummies and use them as weapons to catch fish hiding in crevices?

Taking Care of Home Sweet Home

False clownfish in anemone

A false clownfish in its anemone home. Image taken at the California Academy of Sciences.

In a previous post, I talked about false clown fish, AKA Nemo fish and I mentioned that Nemo had a very special relationship with his anemone and promised a more detailed discussion. Well, here it is.

First a bit about anemones. They are animals that are related to jellyfish and like jellyfish, they have stinging cells called nematocysts (once again, here is the video of nematocysts firing). These stinging cells are filled with venom and they stun fish, which the anemone then consumes. That being said, it hardly seems like a safe place for a small fish to live. However, the clown fish doesn’t get stung by the nematocysts. This is because it has a slimy protective coating on his body (Scientists have been trying to discover whether the fish makes its own mucus coat or if it gets the mucus from the anemone during an acclimation process. Here is one study that suggests that the fish produce their own mucus.) In some cases, anemones also recognize their partners because of a chemical substance that their partners give off and the anemones will rarely try to sting their partners.

So, why have they evolved to tolerate each other? How does each animal benefit from this partnership? Well, the fish gains the protection of the anemone’s stinging cells for itself and its eggs, as potential predators could be stung and consumed by the anemone.

clown fish in anemone

A false clown fish nestled safely in its anemone's protective tentacles. Image taken at the California Academy of Sciences.

The anemone benefits in many ways. First, the small fish might act as a lure for larger fish to come by that the anemone will then sting and consume. The clown fish will also attack fish that try to nibble on the anemone, such as butterfly fish. Even when the attackers are relatively large, the clown fish will defend its home. The anemone can also eat the left over food from clown fish dinners. Lastly, clown fish nitrogen waste will increase the levels of nitrogen in the water. This is good because some anemones have an algae that lives inside of their tentacles called zooxanthellae (the same type of algae that lives in coral). The zooxanthellae makes sugar from sunlight like a plant and shares some of that sugar with the anemone. The nitrogen from the fish waste fertilizes the zooxanthellae which in turn can increase food production and anemone growth. So as you can see, the anemone gains a lot by offering its protection to these small, attentive fish.

False Clownfish: AKA the Nemo fish

Clownfish in anemone

False clownfish in anemone. Image taken at the California Academy of Sciences.

I’m a big fan of the movie Finding Nemo, so the first fish on my blog is Nemo, AKA the false clownfish.  In the picture above, Nemo is carefully tending to his home anemone. In general, false clownfish live in groups with one dominant female, which is the largest fish, a dominant male (the second largest) and then a few male underlings. Just like in the movie, they seldom stray far from the protective arms of the anemone, which is also where they lay their eggs. They will care for their eggs by fanning and guarding them. There’s a lot more to the relationship between Nemo and the anemone, but I will discuss that in depth in a later post.

So the movie certainly got some things right about the life of an anemonefish. However, it did miss one important part of their life history. (Yes, I know it’s a cartoon. What’s your point?) Anyway, in the movie, you might recall that Nemo has a dad but he doesn’t have a mom. But in real life, this would never happen because Nemo, like all false clownfish, is a sex-changing fish. So in real life, if Nemo’s mom died, then Nemo’s dad would turn into Nemo’s mom.  Maybe they’ll make a part 2 and Marlin will be Marla! Yeah, okay, probably not, but my inner nerd loves the thought of scientifically accurate cartoons.

BTW, one thing that’s seriously hurting Nemo’s home in the coral reef right now is that a lot of people like to have brightly colored tropical fish for their home aquariums, and divers don’t always use environmentally friendly ways of getting these fish.  They use dynamite and poisons, for example, to stun the fish to collect them. So, if you’re considering a Nemo for your home aquarium, you can help by asking if your Nemo was raised in captivity and avoiding Nemos that came from the wild.