Tang ID help

[Raazka]

Hi all, I recently bought this juvenile “Yellow Eye Kole (Strigosus)” tang from a LFS but I’ve been wondering if it’s actually a Squaretail (Truncatus)?

Would it be possible to ID it at this age or would I need to wait until it’s older, if so how would I be able to differentiate between the two species?

 

[William Chiavetta]

I think it is a yellow eye. I could be wrong but I'm 80% sure

 

[stewy14]

Yep it’s a yellow eyed kole, according to Google image search

 

[ISpeakForTheSeas]

Hi all, I recently bought this juvenile “Yellow Eye Kole (Strigosus)” tang from a LFS but I’ve been wondering if it’s actually a Squaretail (Truncatus)?

Would it be possible to ID it at this age or would I need to wait until it’s older, if so how would I be able to differentiate between the two species?

Given that the "true" yellow-eyed kole tang (Ctenochaetus strigosus) is reportedly endemic to Hawaii and Johnston Island/Atoll, and given that no fish are currently coming out of Hawaii, I'd say you're right - you probably have a "false" yellow-eyed kole tang, A.K.A. the Squaretail Tang (Ctenochaetus truncatus).

References to C. strigosus from places other than Hawaii or Johnston Atoll are pretty much guaranteed to actually be references for C. truncatus.

Anyway, these fish can be incredibly difficult to tell apart (particularly as juveniles), but there are abfew ways to differentiate them (aside from location), and yours does seem to be a Squaretail Tang:

-The yellow around the eye; the yellow ring is typically larger and less uniformly circular on C. strigosus.

-Body pattern; C. strigosus typically has noticeable striping either dominating or heavily mixed with the spotting on the body; C. truncatus typically just has spots, but they may also have a small to medium patch of striping.

-The tail; as juveniles, both species have similar tails - as adults, C. strigosus keeps its tail shape (crescent shaped with distinct pointy tips on the ends like you would expect streamers to come out from, the tail looks sort of gently curved both on the top and bottom as well as in the center at the end), while C. truncatus' tail transitions to a comparatively triangular/blocky tail shape (rather than curving gently, it just kind of juts straight out both on the top, the bottom, and the center of the end; there's not really any build up to the tips like you get with the crescent shape tails, as its tail is too blocky for any build up).


Your tang still has the juvenile tail, but it has a uniform, small circle around the eye and consistent spotting with no apparent stripes on the body - so 2/3 for Squaretail.

Some references (the ReefBuilder's one has some great pics of both species you can use for side-by-side comparison):

Kole Tang & Squaretail Tang Comparison | Reef Builders | The Reef and Saltwater Aquarium Blog

The bristlemouth surgeonfish of the Ctenochaetus genus are some of the most perfect aquarium fish with a size, behavior and disposition that seems tailor made for a life in a reef tank.

reefbuilders.com

https://www.reefkeeping.com/issues/2003-07/hcs3/index.php

Ctenochaetus truncatus

fishesofaustralia.net.au

Ctenochaetus strigosus (Spotted surgeonfish)

How to keep Spotted surgeonfish in an aquarium. Get some tips on how to care for Ctenochaetus strigosus in captivity and a list of good references for further studies.

reefapp.net

 

[Raazka]

I think it is a yellow eye. I could be wrong but I'm 80% sure

Thank you!!

Given that the "true" yellow-eyed kole tang (Ctenochaetus strigosus) is reportedly endemic to Hawaii and Johnston Island/Atoll, and given that no fish are currently coming out of Hawaii, I'd say you're right - you probably have a "false" yellow-eyed kole tang, A.K.A. the Squaretail Tang (Ctenochaetus truncatus).

References to C. strigosus from places other than Hawaii or Johnston Atoll are pretty much guaranteed to actually be references for C. truncatus.

Anyway, these fish can be incredibly difficult to tell apart (particularly as juveniles), but there are abfew ways to differentiate them (aside from location), and yours does seem to be a Squaretail Tang:

-The yellow around the eye; the yellow ring is typically larger and less uniformly circular on C. strigosus.

-Body pattern; C. strigosus typically has noticeable striping either dominating or heavily mixed with the spotting on the body; C. truncatus typically just has spots, but they may also have a small to medium patch of striping.

-The tail; as juveniles, both species have similar tails - as adults, C. strigosus keeps its tail shape (crescent shaped with distinct pointy tips on the ends like you would expect streamers to come out from, the tail looks sort of gently curved both on the top and bottom as well as in the center at the end), while C. truncatus' tail transitions to a comparatively triangular/blocky tail shape (rather than curving gently, it just kind of juts straight out both on the top, the bottom, and the center of the end; there's not really any build up to the tips like you get with the crescent shape tails, as its tail is too blocky for any build up).


Your tang still has the juvenile tail, but it has a uniform, small circle around the eye and consistent spotting with no apparent stripes on the body - so 2/3 for Squaretail.

Some references (the ReefBuilder's one has some great pics of both species you can use for side-by-side comparison):

Kole Tang & Squaretail Tang Comparison | Reef Builders | The Reef and Saltwater Aquarium Blog

The bristlemouth surgeonfish of the Ctenochaetus genus are some of the most perfect aquarium fish with a size, behavior and disposition that seems tailor made for a life in a reef tank.

reefbuilders.com

https://www.reefkeeping.com/issues/2003-07/hcs3/index.php

Ctenochaetus truncatus

fishesofaustralia.net.au

Ctenochaetus strigosus (Spotted surgeonfish)

How to keep Spotted surgeonfish in an aquarium. Get some tips on how to care for Ctenochaetus strigosus in captivity and a list of good references for further studies.

reefapp.net

Thank you so much for the incredibly detailed response and the sources! Definitely was starting to lean towards him being a C. Trucantus the more I looked into it. I’d guess the little guy was mislabeled by the store or their supplier, still love him a lot though aha.

 

[Septurn]

Hi all, I recently bought this juvenile “Yellow Eye Kole (Strigosus)” tang from a LFS but I’ve been wondering if it’s actually a Squaretail (Truncatus)?

Would it be possible to ID it at this age or would I need to wait until it’s older, if so how would I be able to differentiate between the two species?

It's definitely a yellow eye.

 

[William Chiavetta]

Thank you!!


Thank you so much for the incredibly detailed response and the sources! Definitely was starting to lean towards him being a C. Trucantus the more I looked into it. I’d guess the little guy was mislabeled by the store or their supplier, still love him a lot though aha.

I guess I was wrong. Sorry!