- I think everyone has heard
about shrimp that set up cleaning stations on coral reefs.
You're probably also familiar
with the wrasses that do the same thing.
They eat the parasites off the client fish
that come to their stations.
But have you ever heard
of a pygmy angelfish cleaning off parasites?
Hi guys and girls, I'm ReefMan,
and today we are talking about the very first report
of cleaning by a pygmy angelfish.
If you would like to read the paper,
it's linked down below as usual.
It was published in the Journal of Coral Reef Studies
in late 2020.
Cleaner fish and shrimp fill an important role
on coral reefs and even in our aquariums.
They clean up parasites and clean off dead tissue
and mucus from their clients.
They'll even clean your skin
when you're working in your aquarium.
They'll give you an at-home manicure
if you don't mind them picking away.
There are two general types
of cleaner animals on coral reefs.
Dedicated cleaners are animals that spend
their entire lives cleaning other animals.
They get 100% of their food from eating those parasites
and they can eat quite a few of them,
even though they're very small,
small enough to fit in the gills and the mouths
of their clients.
The bluestreak cleaner wrasse
can clean almost 2,300 fish every single day,
removing about 1,200 parasites from their skin.
And that's in a single day.
For this reason, fish like the bluestreak cleaner wrasse
don't make the best aquarium inhabitants,
unless you have a truly gargantuan tank.
They get all of their food just by eating those parasites
and hopefully our aquariums don't have that many parasites,
so they go hungry.
The gobies and wrasse, in general,
encompass every known dedicated cleaner species.
The second group of cleaners is called facultative cleaners.
These are just opportunistic cleaners
that will eat other foods,
as well as the parasites off other fishes skin.
Wrasse are the most common facultative cleaners
and we know of 63 different wrasse species that do it.
But wrasse are not the only reef fish
that sometimes clean other fish.
Some angelfish do,
specifically Holocanthus and Pomacanthus angelfish,
and some butterflyfish are also known to do this.
All told, we know of 208 fish
and 51 species of shrimp that set up stations
to clean other reef fish,
but we've never seen a pygmy angel fish maintain
a cleaning station, until now.
The authors of the paper noticed cleaning behavior
from both bicolor and keyhole angelfish
in a huge 20-foot-tall aquarium
at the James Cook University in Australia.
While it's true,
this is the first time that pygmy angelfish
have been seen to clean other fish.
They didn't actually appear
to be particularly well suited for the task.
Several times, the client fish jolted,
probably because a painful bite was delivered
by the overzealous cleaner.
Pygmy angelfish have a comparatively strong bite,
as opposed to more common cleaners, like wrasse or shrimp,
which just carefully pick things off the surface
of the skin.
The weaker bites
of those more common cleaner fish decrease the chances
of collateral damage happening while cleaning.
They also tend to have behavioral and physical adaptations
that allow them to carefully clean
and communicate with their clients via fin movement.
Imagine a shark trying to carefully nip off a tiny parasite.
It's just not gonna happen.
Pygmy angelfish, on the other hand,
have no adaptation, like those sharks don't, for cleaning
and their mouths have bites that are designed
for cutting through tough sponge and algae growing on rocks,
which is what they eat in the wild.
It's also possible that this is really just a behavior
that only ever happens in captivity.
The tank in Australia didn't have any dedicated
or facultative cleaners in it,
so it's possible that the angelfish
are just taking advantage of the situation.
We do see that in lumpfish,
which are raised with farmed salmon,
just to eat the parasites off their skin,
but they only ever do that in farm settings
and not in the wild.
There is some evidence that this isn't the case though,
that these angelfish were able to communicate
with their clients
via their fins and body movement.
Lumpfish, they don't do that.
And we know for sure
that the angelfish were because we could see it happen.
So there is at least some evidence that this isn't something
that's only happening in captivity.
Have you ever seen angelfish cleaning your tanks
or larger fish in your tanks?
I certainly haven't, but it is possible, apparently.
I'm very curious if you've seen things
like this in your tank.
My Potter's angelfish,
they pick at rock and things like that all day long,
but never at my Achilles tang,
who pretty much just totally ignores them.
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I hope you had a great holiday season,
and here's to a better 2021.
Stay safe.
Have a fantastic day.
Bye.