Kryptopterus

[The.Dark.One]

K. macrocephalus?

[Marc van Arc]

I don't think so. Afaics your specimen lacks the typical "lipstick" pattern in the mouth area (obviously) and I also think it's too transparent for a K. macrocephalus.

[The.Dark.One]

with it having a large head (macrocephalus) I thought it could be that. K. minor then? The fish is about 8cm SL.

[Silurus]

This is indeed K. macrocephalus.

[The.Dark.One]

Thanks Silurus

[sidguppy]

I thought

Kryptopterus macrocephalus

was supposed to be mottled.

the form we get in the trade here (it's not regular, but not very rare either) is alays the one like this, only a more brown coloration than silvery.

I never seen macrocephalus transparant over any size bigger than 5-6 cm TL.

the Catelog shows mottled as well as transparent specimen
what are the visible differences between a transparant

Kryptopterus macrocephalus

and a

Kryptopterus minor

?

is it possible that there are more local varieties in K macrocephalus (transparent, silvery mottled, brown mottled)?

[Silurus]

what are the visible differences between a transparant

Kryptopterus macrocephalus

and a

Kryptopterus minor

?

The easiest way to tell them apart is size (K. macrocephalus is bigger), and the fact that the nuchal concavity on K. macrocephalus is more pronounced, giving it a more humpbacked look.

is it possible that there are more local varieties in K macrocephalus (transparent, silvery mottled, brown mottled)?

AFAIK, there are only two forms: striped (all of the “transparent” ones are striped forms with faded/indistinct stripes) and mottled. Some are more yellowish than others (I find that freshly-caught fish from backwater habitats tend to be like this).