# Attention Serrasalmus Experts



## below (Mar 26, 2004)

In nearly every picture I have seen labled as S. rhombeus, the fish has a distinct black edging on the outer edge of the caudal fin. This seems to appear even in very very young specimens. My question, then, is: is this black edging to the tail distinctive of S. rhombeus or can other species have it as well?

Also, does S. rhombeus have an amber coloured splotch on the gill-plate as a juvenille or is this only found in S. spilopleura?

The reason I ask is that I have been doing extensive research trying to muddle through some of the mis-information regarding species of the Serrasalmus family and I have come across many instances of identical pictures being labled as both S. rhombeus and S. spilopleura.

The young Serrasalmus that I care for has no terminal black band on it's tail (only at the base--the rest of the tail is completely transparent), has a red-tinged anal fin that darkens where it meets the body and has the above-mentioned amber splotch on the gill plate.

Just trying to gain some insight into whether this piranha that was labeld simply "Black Piranha" might be S. rhombeus or S. spilopleura.


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## rufus (Jan 6, 2004)

spilos also have the black stripe across the rear fin


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## Red Eyes (Nov 25, 2003)

> ... The young Serrasalmus that I care for has no terminal black band on it's tail (only at the base--the rest of the tail is completely transparent), has a red-tinged anal fin that darkens where it meets the body and has the above-mentioned amber splotch on the gill plate...


I'm no expert , when rhoms and spilos are young they both have these traits so it is difficult to identify which is which. This is the reason why if you look in the species identification forum there are so many posts asking if "this is a rhom?"


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## erikcooper (Feb 18, 2004)

Move it to Frank's forum, he can help you for sure


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## andymel (Oct 27, 2003)

It is almost impossible to tell the two species apart when they are very young.


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## traumatic (Jan 29, 2003)

the terminal band on the caudal fin is a distinctive trait of S. Rhombeus, Though in S. Spilopleura (syn. to S. Maculatus) the caudal fin edging is hyaline (clear) and w/ a black subterminal band. In S. Spilopleura complex form (ruby red, or being debated as true spilo) there is also a black terminal band. Thus the confusion of identifying young Spilos, and young rhoms. The amber gill coloration can and will be similar between these fish when small. With S. rhombeus, the color never seems to spread past the gill plate. Though in spilopleura, the coloration will spread throughout the belly as it grows. Hope this helps.

please visit opefe


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## below (Mar 26, 2004)

thanks guys


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## Grosse Gurke (Jan 3, 2003)

The tail you described is the tail of S. altisipinis (Spilo cf). I think this also depends on the size of your fish.

Moved to Franks forum.


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## hastatus (Jan 16, 2003)

Here is a link that might be of some help. Skim down on that page, there is a photo summary of "tails".


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