Need Help With Tetra ID

[powerdyne6]

Picked a group of 10 of these up. They were labelled as “Blue” Tetra

Just curious which species I may have bought

Pictures are tough to get as they don’t like to stay still

 

[powerdyne6]

Video uploaded

 

[powerdyne6]

One more video

 

[BettaFishGirl]

I can't help you with identifying them but they are really pretty!

 

[Wills]

I think these are Cochu's Blue Tetras - but when I google it, it looks like the scientific name has changed from what I knew it as and it is now the hilarious-sounding Knodus Borki...

Wills

 

[BettaFishGirl]

the hilarious-sounding Knodus Borki...

"Oh yea, I have some Knodus Borki's over here"

 

[powerdyne6]

I think these are Cochu's Blue Tetras - but when I google it, it looks like the scientific name has changed from what I knew it as and it is now the hilarious-sounding Knodus Borki...

Wills

This is what I first thought they were but asking around this species came up

Boehlkea fredcochui summary page

www.fishbase.se

Seriously Fish doesn’t have a listing for this species.

 

[Byron]

There are two different species being mentioned here, not one. I find they are remarkably similar, but the fish in @powerdyne6 tank are pale as they are new. When they colour up it might be easier to identify. The two species are:

Boehikea fredcochui

Described by Gery (1966) in "A review of certain Tetragonopterinae (Characoidei), with the description of two new genera," Ichthyologica, the Aquarium Journal v. 37 (no. 5): pp. 211-236. I do not have access to this, but Gery gives their origin as "upper Amazon" in Colombia. Zarske, a close friend of Gery who will reappear below, agrees with this as a distinct species. Eschmeyer's Catalog of Fishes, the pretty-much final authority on taxonomy, has the range as the Amazon basin (Brazil, Ecuador, Colombia and Peru) and several other references accept the species.

Knodus borki

Described by Zarske (2008) as a distinct species with the type specimens collected near Iquitos in Peru. The description of this new species is in German but the English Abstract mentions the differences:

A new Characid fish – Knodus borki sp. n. – is described from the surroundings of Iquitos in Peru. Knodus borki sp. n. is distributed as Boehlkea fredcochui GÉRY, 1966 since many years by aquarium trade. Both species differ mainly in the dentition of maxillary bone (three to four tricuspid or conical teeth in Knodus borki sp. n. vs. 11 to 21 tricuspid and conical teeth in Boehlkea fredcochui) and in colouration. Knodus borki sp. n. is closely related with Knodus megalops MYERS, 1929. Both species differ (1) in lateral line (incomplete in Knodus borki sp. n. vs. complete in Knodus megalops), (2) in the size of eye (2,46–3,24 times SL in K. borki sp. n. vs. 2,2 times SL in K. megalops), (3) in body depth before dorsal fi n (2,91–3,34 times SL in K. borki sp. n. vs. 2,9 times SL in K. megalops), (4) in head length (3,94–4,65 times SL in K. borki sp. n. vs. 3,8 times SL in K. megalops) and (5) in the colouration.​

I think this new species has been in the hobby under the name of the older species, if I am reading Dr. Zarske's opening Abstract sentences correctly. Eschmeyer's Catalog has both species with several references each confirming the taxonomy of two distinct species.

powerdyne6 is going to check with the store (it is near me) to ascertain the scientific name from their invoice.

 

[Wills]

There are two different species being mentioned here, not one. I find they are remarkably similar, but the fish in @powerdyne6 tank are pale as they are new. When they colour up it might be easier to identify. The two species are:

Boehikea fredcochui

Described by Gery (1966) in "A review of certain Tetragonopterinae (Characoidei), with the description of two new genera," Ichthyologica, the Aquarium Journal v. 37 (no. 5): pp. 211-236. I do not have access to this, but Gery gives their origin as "upper Amazon" in Colombia. Zarske, a close friend of Gery who will reappear below, agrees with this as a distinct species. Eschmeyer's Catalog of Fishes, the pretty-much final authority on taxonomy, has the range as the Amazon basin (Brazil, Ecuador, Colombia and Peru) and several other references accept the species.

Knodus borki

Described by Zarske (2008) as a distinct species with the type specimens collected near Iquitos in Peru. The description of this new species is in German but the English Abstract mentions the differences:

A new Characid fish – Knodus borki sp. n. – is described from the surroundings of Iquitos in Peru. Knodus borki sp. n. is distributed as Boehlkea fredcochui GÉRY, 1966 since many years by aquarium trade. Both species differ mainly in the dentition of maxillary bone (three to four tricuspid or conical teeth in Knodus borki sp. n. vs. 11 to 21 tricuspid and conical teeth in Boehlkea fredcochui) and in colouration. Knodus borki sp. n. is closely related with Knodus megalops MYERS, 1929. Both species differ (1) in lateral line (incomplete in Knodus borki sp. n. vs. complete in Knodus megalops), (2) in the size of eye (2,46–3,24 times SL in K. borki sp. n. vs. 2,2 times SL in K. megalops), (3) in body depth before dorsal fi n (2,91–3,34 times SL in K. borki sp. n. vs. 2,9 times SL in K. megalops), (4) in head length (3,94–4,65 times SL in K. borki sp. n. vs. 3,8 times SL in K. megalops) and (5) in the colouration.​

I think this new species has been in the hobby under the name of the older species, if I am reading Dr. Zarske's opening Abstract sentences correctly. Eschmeyer's Catalog has both species with several references each confirming the taxonomy of two distinct species.

powerdyne6 is going to check with the store (it is near me) to ascertain the scientific name from their invoice.

That’s really interesting thanks Byron I thought the Boehikea had been reclassified.

Wills

 

[Ichthys]

The blue tetra in the hobby has always been Knodus borki, but it has always been misidentified as Boehlkea so that’s what the shop will probably say it is. Boehlkea is not in the hobby afaik.