Various tetra species

[duanes]

These are Roeboides ilseae, often called the vampire, glass headstander.
Here in Panama called Sardinita (as are almost all similar shaped tetras)
They were caught in a tributary of the Rio Chagres (central Panama) about 3 years ago for me by a friend, along with some Andinoacara coerleopuntatus, and which they have shared a 180 gal tank with ever since, in pH 8.2 water.
They are scale eaters, and occasionally take a mouthful of scales off the cichlids, or even each other.
They also eat mosquito larvae, small local shrimp, and chopped fish flesh.
Whenever I get a red snapper, or mackerel fro myself, they get the trimmings.


They come from mineral rich, high pH waters all over Central America, so are perfect dithers for these type, medium size cichlids.
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[Deadeye]

Technically piranhas count for this thread.

I think the red bellied piranha has a potentially appealing attribute that's almost always overlooked because it's a piranha: the classic red belly. Now I don't keep them as I much prefer loaches to piranhas, but if I did keep them, the visual appeal of that bright red belly would be my #1 reason to.

View attachment 1490634
Image by National Geographic Kids.

I even suspect that if there was a silver dollar species colored like this, it would be very popular because of said color. Anyone have any thoughts on this?

Technically piranhas aren’t tetras. Nor are silver dollars. They are of a different family, but both are characins (and rather closely related compared to others).
That said, most RBP do get duller with age, but that doesn’t stop them (and other piranhas) from being one of the most popular fish on this forum (after all, it is called MONSTER fish keepers). On my top 5 favorite fish of all time (second favorite freshwater fish after banded leporinus). The big problem is that they are illegal in many states.
Silver dollars are also one of the most popular fish - they may not have much color (though many species do), but the reflective silver scales make for an amazing show fish.

 

[MultipleTankSyndrome]

Technically piranhas aren’t tetras. Nor are silver dollars. They are of a different family, but both are characins (and rather closely related compared to others).

Seriously Fish puts silver dollars and piranhas in the Characidae family, subfamily Serrasalminae (although, probably because of a typo, this is absent on the red belly piranha page).
Is that considered wrong nowadays?

 

[Deadeye]

Seriously Fish puts silver dollars and piranhas in the Characidae family, subfamily Serrasalminae (although, probably because of a typo, this is absent on the red belly piranha page).
Is that considered wrong nowadays?

I’m pretty sure (at least according to the super reliable Wikipedia taxonomy) the order is characiformes and the family is serrasalmidae (but you are right that that is also considered a subfamily in the characidae family). So I guess it’s up to interpretation and the muddy water waters that is taxonomy. But I guess the moral of the story is that they technically aren’t in the same group and are separated - but still close relatives - but not enough to be considered true “tetras.”

 

[MultipleTankSyndrome]

But I guess the moral of the story is that they technically aren’t in the same group and are separated - but still close relatives - but not enough to be considered true “tetras.”

The characid family is the same group, no? That's the same family as everything else in this thread, and is also considered the tetra family.
I don't trust Wikipedia as much as sites like Seriously Fish because not only can anyone put anything in there, they have a bunch of fish taxonomy pages in red (meaning they didn't bother making a page on it, while they would be expected to).

If we're talking about characid piranhas and silver dollars (which I see no reason to doubt as the most likely classification), to say they're not in the same group as tetras and not close enough to be considered true tetras is equivalent to saying African and South American cichlids (both in the Cichlidae family but different subfamilies, like the tetras/piranhas) are not in the same group and not close enough to both be cichlids.

 

[Deadeye]

Tetra is a common name which only refers to the small schooling fish.
The family/subfamily serrasalmidae is what separates piranha from tetras (which are part of multiple other families/subfamilies) due to various genetic and morphological differences.
To call a piranha a tetra is essentially like calling a mbuna an Oscar - they are related by both being Cichlids (like how a piranha and tetra are both characins), but that doesn’t make it an Oscar (tetra).

 

[MultipleTankSyndrome]

That definition of tetra will always be somewhat subjective. I personally don't agree with it because there are large serrasalmines known as tetras (disk tetras), so I see no reason to exclude piranhas either because of it.

 

[esoxlucius]

I've never really been a tetra fan, up until a couple of weeks ago. May I offer the humble rummynose tetra as my choice. I bought half a dozen to go with my three rams in my hex tank. Absolutely delightful little fish, and an added bonus with this fish, they are relatively long lived for such a small fish, up to 8 years if conditions are favourable.

 

[PhishMon84]

Most of my fish keeping friends refer to malawi cichlids as malawi tetras... just because they so over done.

 

[duanes]

For those who doubt that piranhas, and pacu are tetras.
Scroll down to classification

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwjbgdXW_NL2AhXzQjABHWNDBZsQFnoECAkQAQ&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FPacu&usg=AOvVaw1Zxe0yYEdmyxJSMbftHnvD