Impurest's Guide to Animals #162 - Glass Catfish

Winter is not yet over, as another storm rolls into the coast. As the wind and rain bares down on us, dreams of an early spring see to be fading. The subject of last week’s issue, the Casque Headed Frog certainly wouldn’t stand this weather. Neither would this week’s transparent request from @lordofthelight, hope you guys enjoy. _________________________________________________________________

Issue #162 – Glass Catfish

Kingdom – Animalia

Phylum – Chordata

Class – Actinopterygii

Order – Siluriformes

Family – Siluridae

Genus – Kryptopterus

Species – vitreolus

Related Species - The Glass Catfish is one of eighteen species found within the genus Kryptopterus

Range - Glass Catfish are endemic to the rivers south of the Isthmus of Kra in Thailand

Ability: Clear Body

The Glass Catfish is a small fish which reaches a body-length of 8cm. This species has transparent skin that allows observers to see the fish’s internal skeleton and organs, although the later can only be detected with the use of a magnifying glass or microscope. The biology behind this transparent skin comes from a lack of pigments in the fishes flesh as well as the lack of scales, something that’s a common trait among catfish (2). That said when the Glass Catfish is sick or dying, its body tints white, and its organs are unable to be seen from the outside of its body.

Glass Catfish are omnivores, feeding on vegetation and aquatic invertebrates found in suspension in the water column that is locates using chemical cues with the whisker like barbells hanging from its chin. To evade its own predators the Glass Catfish relies on its transparent body against the dark water it lives in to remain unseen. While other species of catfish have venomous spines on the dorsal fin, the Glass Catfish lacks this defence, and has reduced fins across its entire body, possibly to aid it in being undetected by its enemies.

Glass Catfish prefer to breed during monsoon season when a regular supply of freshwater is entering the river, since their initial courtship dance requires both the male and female to swim close to each other, often running their ‘whiskers’ down the flank of the other fish involved. Eggs are laid on the underside of aquatic vegetation soon after mating, and the male fertilises them almost immediately, with the young emerging within days as tiny versions of the adult fish.

Five Transparent Animals

The Crocodile Icefish (Family: Channichthyidae), unlike the Glass Catfish, gets its transparent looking appearance from the lack of both haemoglobin and myoglobin in its red blood cells in addition to having scaleless skin. Thanks to such a low metabolism and the cold yet stable environment it inhabits, the low amount of oxygen that the Icefish needs can be transported in the blood plasma (3).

Pale and transparent skin is common in deep sea organisms due to a lack of light reaching the areas these animals inhabit. One such animal is the amphipod Phronima, a parasitoid of a group of tunicates known as Salps. It is theorised that being transparent acts as camouflage when the amphipod burrows into the Salp (which is transparent itself) to lay its eggs, thus reducing potential predation of the next generation.

Male Reticulated Glass Frogs (Hyalinobatrachium valerioi) also use their transparency to aid in protecting the next generation. The patterning visible through the frog’s skin resemble the groupings of eggs, which the female lays on a leaf overhanging water, that he guards for their two week development period. When attacked, the frog will wait for potential egg predators to get close to him, before repelling them away from his brood with aggressive kicks, until they are ready to hatch.

Some animals are only partially transparent, with the Clearwing Butterfly (Greta oto), being one of the few terrestrial animals to have no pigmentation on large portion of its body. The wings of the butterfly, sans the veins are made of a material that has a low absorption rate and low scattering rate of natural light, thus causing the structure to look transparent.

The Barreleye (Macropinna microstoma) is also semi-transparent. The fish developed a large transparent fluid filled dome to protect its upwards facing eyes from the stings of the jellyfish it steals food from. In addition to protecting the eyes, it is also thought that this domes also refracts light with a wavelength equal to that of seawater entering the structure, much like the lens found in an eye, aiding it in detecting both prey and predators (4).

Bibliography

1 -www.arkive.org

2 - Bruton, Michael N. (1996). "Alternative life-history strategies of catfishes" (PDF). Aquat. Living Resour. 9: 35–41.

3 - Holeton, George (2015-10-15). "Oxygen uptake and circulation by a hemoglobinless Antarctic fish (Chaenocephalus aceratus Lonnberg compared with three red-blooded Antarctic fish". Comparative Biochemistry and Physiology. 34: 457–471

4 - https://www.newscientist.com/article/dn16341-first-vertebrate-eye-to-use-mirror-instead-of-lens/

Picture References

1 - http://aquaticmag.com/wp-content/uploads/2014/10/Kryptopterus-minor-glass-catfish-ghost-fish-catfish-x-ray-fish-Informaiton-caresheet-wiki-glass-catfish-ghost-fish-catfish-x-ray-fish-for-sale-and-where-to-buy-AquaticMag-6.jpg

2 - https://static1.squarespace.com/static/56cc4852356fb0ad1dc8bc20/t/575e93a71ccbd10cb5d853a9/1465819051824/amyc0eezg.png

3 - https://whyevolutionistrue.files.wordpress.com/2010/08/pelagic-amphipod-phronima-008.jpg

4 - http://puzzles-games.eu/data/media/1/Clearwing-Butterfly.jpg

5 - http://www.mbari.org/wp-content/uploads/2016/01/barreleye1-350.jpg

And that’s an issue featuring the creatures whose bodies are clear as day. Next week we have one of the most ecologically important animals to ever exist. But until then make sure to critic, comment and suggest future issues as well as making sure you check past issues in Impurest’s Bestiary

Many Thanks

Impurest Cheese

Want more IGTA? Want a catfish with a little more bite? Click here to check out the (potentially) man eating Goonch Catfish. Or click here to meet the grumpy looking Bearded Ghoul.

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Clear as Glass?

Nice.

Also, yes I did notice it was windy today.
Today being the day I have to carry around a big A2 sketchbook with me everywhere

Wow that's really fascinating!

O_o The Barreleye is eerie looking... wikipedia says they're also known as "spook fish", that feels appropriate lol

@emperor339: Je desole, now imagine trying to climb a stand of beech trees to check holes thirty foot up in the trunk for bats. That's what I had planed to do today, fortunately the survey was called off.

Also thanks for the comment :-)

@amendment50: Thanks, really have to thank the guy who requested this issue. And yes Spook Fish is an appropriate name, always remember seeing this in Blue Planet and being amazed at how different it was.

they repel predators by looking like they've already been eaten XD

@amazing_webhead: Up until they explode out of their still living hosts that is.

Dang, I want one of those for my fish tank. That would be one heck of a conversation starter.

@mrmonster: Which one? Glass Cats are hard to keep in captivity, the other two are impossible.

Ha! they look funny and invisible

Damn, transparency is by far one of the coolest looking things. At first glance I thought the glass catfish was just a head and really long fin.

Damn, that's really nice, it looks like they have a natural diaphanization technique, lol.

Btw, it's actually hard to see their fins. :P

@impurestcheese: I should really just look this up, but are needlefish transparent too?

The barreleye looks like a fish version of an R3 unit.

I love to eat catfish and that there looks like it wouldn't do much to wet my appetite. It does have the internal structure of a catfish, though.

Wow. Never knew that thing existed. Thanks for the insight.

@pipxeroth: In that case, its cryptic (lack of) colouring has been successful. Thanks for the comment.

@anna_karenina:We're not quite sure why that happens. As for the fins...well the Latin name translates to Hidden Glass Fins, obviously it's well named.

@ficopedia: Nope gar or needle fish are silvery not transparent. Thanks for the comment though.

@xwraith: Can't deny that, although I think the Barreleye has been doimg it longer TBH

@dshipp17: It's not a very big fish either. Now a big ole Wels like we have here in Europe...that's another story.

@toratorn: No problem, thanks for the comment

@impurestcheese: that's pretty cool, i actually never knew these specific types existed, especially the near transparent butterfly!

Do you think a Great White Shark would still be intimidating if it had transparent skin? (let's say just only around the belly and fin)

I was aware of a glass fish but I don't recall a catfish. Pretty cool.

I've never seen that barreleye either. Any idea what year it was discovered?

I wonder how they taste

Cool, I love transparent animals.

@solid_snake97: Nah the Great White has pretty good countershading, plus it would mean that the belly sin would be thin, and prone to damage by struggling prey. Thanks for the comment on the Clearwing it's a pretty cool animal

@jloneblackheart: Cool thanks. The Barreleye was discovered in 1939, but all the specamins had been deformed by the change in pressure, so the domes were not recorded until it was encountered in the wild in the early 2000s

@jaycool2: Not good probably, there isn't much to eat on it TBH

@major_hellstorm: They are pretty cool. Thanks for the comment

Damn, that is cool as.

Surprised you didn't save this for October.

@black_wreath: Thanks, this was a request issue so it's timing was a lityle arbitrary. As for Shocktober Part 2, I already have a tentative line-up ready for it.

Awesome :)

Reminds me of electronics that use see through plastic

Very cool

I don't have much to say on this one.

The frog is pretty cool. Neat trick looking like your own eggs to protect them.

I think the butterfly is pretty cool looking.

@heroup2112: Yeah I almost went for something else for the second segment, glad I went with this insteaf

@captainmarvel4ever: They are cool indeed

@jaycool2: Then they have succeeded in their mission (at least partially)

@laflux: Thanks for the comment

"...their initial courtship dance requires both the male and female to swim close to each other, often running their ‘whiskers’ down the flank of the other fish involved."

Oh my, how lovely and sensual these fish are!

I have to say, that butterfly is incredible. Imagine coming across something like that in the wild. There's a conservatory near where I live, I should ask if they have any about. If they don't, they should.

@ms-lola: Yeah its nice to cool down after a hectic day and just hang with the one you love

I think the Glass Butterfly is protected by C.I.T.I.E.S (Convention on International Trade in Endangered Species of wild fauna and flora) so it would be hard to legally export from its homeland