PlanetCatfish.com

now that I have your attention. Whats the deal with calling every oto thats not a zebra, Affinas?

I say

What say yee?

For those who are wondering it's the one on the right

1) Why are so many otos identified as "Otocinclus affinis". Beats me. Possibly they really mean something like, say, Otocinclus sp. aff. vittatus (meaning "this is a new species of Otocinclus which seems closely related to vittatus"), but more likely they're following some book.

2) Your fish is not a macrospilus, on account of it having a contiguous lateral pigment band, but other than that I can not say.

I like the topic , and I agree! But they are damn cute!.

Can't help you with the ID though, will leave that up to the experts.

They are pretty neat for something that is functional in the tank.

I had an Oto like this I got with some other more "common" otos, the main difference I was able to see was the large eye, and it seemed to be nocturnal. I think they are labeled as affinis because they are all caught and shipped together, and 99% are affinis.

Well if both the Cat-e-log AND Fishbase are wrong and looks totally different then this then I'd agree. I'm thinking most are a mix. The locality of many smaller fish is all over the place.

The Otocinclus affinis on Planetcatfish picture is the right species, although it's either dead or scared. It should have a very narrow unbroken black band along the side. You can see it if you look closely, but it's very pale. The golden gleam is however typical of the species.

For what it's worth, it seems as though O. affinis is very rare in the trade. I've never seen a real O. affinis for sale.
Incidentally it's the much same with the OTHER name commonly tacked on otos: Otocinclus vestitus. Pretty much no fish sold as either O. affinis or O. vestitus, are.

I agree. This one just had the oscell(sp?) spot of the sp I thought it was....