Bannerfish vs Schooling Bannerfish

[Deefstes]

Hi all,

I'm hoping someone could explain to me (or even point me to pictures illustrating the difference) how to tell Bannerfish/Coachman (Heniochus acuminatus) apart from Schooling Bannerfish/Schooling Coachman (Heniochus diphreutes).

I've read somewhere that there's something about the length of the snout and the roundness of the body but none of these features seem to be obvious to me. Any advice?

Thanks,
D

 

[AlaskaDiver]

D;
This is the website I found with a picture explanation of the differences between the two. I hope it helps. Fish of The Week

 

[Deefstes]

OK, I've done some reading since and I think I may have found a way to tell the two apart with a fair level of certainty.

There are four features to look for it seems. I've had a look at loads of pictures and the first three seem to hold true in most cases while the last one held true in just about all cases.

1. The demarcation of the central white band and the second black band run from the dorsal fin to the anal fin. The line terminates at the tip of the anal fin on H. diphreutes while it terminates slightly higher up than the tip of the anal fin on H. acuminatus.

2. The tip of the anal fin more or less forms a right angle on H. diphreutes while on H. acuminatus it forms a sharper than 90 degree angle.

3. H. diphreutes have more of a rounded chest than H. acuminatus. This feature to me is probably that toughest one to really get my head around and I'm not sure it's of much use really.

4. Finally, the amount by which the mouth protrude from the face seems to be a pretty good feature. The length measured from the tip of the mouth to the forward edge of the eye is roughly equal to the diameter of the eye on H. diphreutes while on H. acuminatus it is slightly more than the diameter of the eye. I've attached an image that illustrates this. There are better pictures out there on which you can check the feature but these are the only ones for which I won't violate copyright.

 

[AlaskaDiver]

Very impressive in your methodical means of comparing and contrasting between the two. Thank you!