這篇文章論點不一定正確
個人的感想而已
剛開始進入虎魚領域時，S. spilopleura中文是取名黃鑽虎魚
有些黃鑽虎魚的尾巴黑線是在中間(雜誌所說的黃金虎魚)，有些黑線至尾端。
有時覺得一開始，學名是不是一開始就搞錯了
S. maculatus在幼魚時期，尾鰭黑線在中間，但隨成長發育的尾鰭黑線延伸到邊緣薄透明結尾，但大多數S. maculatus尾鰭黑線都是黑線結尾。
S. spilopleura則不會有透明結尾的特徵。
S. maculatus keeps its midline terminal band as young specimens (usually under 2 inches TL), but then during its growth its midline band extends out to a thin hyaline edge on the tail (caudal fin). Most often the thin hyaline edge on S. maculatus is not present, but becomes a complete dark band. With S. spilopleura, a few specimens have been observed with a total black tail and dark body, these are often breeding adults. The same coloration of the tail is sometimes reported for S. maculatus and is fairly common for most piranha species.
S. spilopleura is a solitary species, unlike S. maculatus which may travel in small groups. This is largely an individual species choice and any such group gathering is never long lasting. Indeed, the group itself is largely based on orientation of same size, So some individuals may leave the group and join others of same traits and attributes.
參考
http://www.angelfire.com/biz/piranha038/spilopleura.html
但是同個網站，另一篇卻說S. spilopleura 尾鰭黑線會保持中間
真正的S. spilopleura特徵為紅橙色的眼睛，明亮的紅腹。而S. maculatus，為金黃色的肚子。
若真是如此，S. spilopleura其實就是"紅鰓黃鑽"，因為過去大家所認知的S. spilopleura都是金黃色肚子。
S. maculatus is more widespread and likely the species most often encountered in the hobby trade. Including bred in captivity. The midline band is visible on very young species but as maturity sets it this midline band become terminal or one can observe a very thin hyaline edge on the caudal fin. On the other hand,
S. spilopleura maintains its midline band throughout its life. The best that I can interpret from this complex description is the real S. spilopleura exhibits a reddish-orange eye, bright red belly. While S. maculatus is found as a golden-yellow belly throughout its range.
參考
http://www.angelfire.com/biz/piranha038/maculatus.html
參考文獻
http://www.wretch.cc/blog/rickyboss1/14348454(rickyboss)
http://www.angelfire.com/biz/piranha038/index.html
