peruvian flounder

grmanrocks

grmanrocks

Jack Dempsey
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Apr 22, 2006
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my lfs has a few "giant peruvian flounders". i want to get one for my 100 gallon and just had a few q's:

what is their scientific name?
what do they eat? frozen bloodworms? feeders?
r they actually freshwater or do they need brackish?

thnx in advance..........
 
matty

matty

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Hmm, Peruvian. The most commonly seen freshwater sole (at least in the UK) is Catathyridium jenynsii (formerly Achirus errans) which is usually imported from Brazil. There are a few species in the genus Trinectes found in South American freshwaters but as far as I know these stay quite small. All of them need a sandy substrate so they can exhibit their natural behaviour, and very dim lighting as they feed at night. They are carnivorous and will take bloodworm, earthworms and similar(including smaller fish). As for the "giant" bit, max size for Catathyridium jenynsii is around 8" although there are reports of them reaching a foot. Lots of folk say they are hard to keep alive in captivity but this is usually down to misidentification as some brackish species are sometimes sold as freshwater. Hope that helps mate.
 
Oddball

Oddball

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Sorry, I had 2 bone grafts done yesterday. Then, I was in pain-killer La-La land. The closest ID I've been able to garner is the same as matty's. I believe the species is Catathyridium jenynsii. I'm doing a search of SA university library archives and have ruled 2 other possibilities out. Once I'm out of med-fog I'll translate the other papers my 'puter located. I'm looking, primarily, for the physiological field collection data for this species to match scale and ray counts to a couple of DOA peruvian flounders I have in preservation.
 
matty

matty

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Hi Oddball if I read that right you're thinking that Catathyridium jenynsii may also occur in Peru? I would find that interesting as so far all the species in the genus have only been recorded in Eastern South America. Looking forward to your findings :popcorn:
 
grmanrocks

grmanrocks

Jack Dempsey
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thnx guys, ive got 2 of the best on the case...... ive been doin it for months... google sucks..... thnx
 
Oddball

Oddball

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matty;589383; said:
Hi Oddball if I read that right you're thinking that Catathyridium jenynsii may also occur in Peru? I would find that interesting as so far all the species in the genus have only been recorded in Eastern South America. Looking forward to your findings :popcorn:
Click to expand...
I know. That's my main problem with the ID. I can't find any publication on these true FW flounders. So far, only articles describing several SW species venturing into FW, However, the eye placement and jaw structures are all wrong. The eastern species is, so far, the closest match. Checking for species divergence through, possibly, previously linked waterways. Also checking for locality field collection notes. The main limitation is the scarcity of internet-available info. Alot of these notes are in bibliography references but, have yet to be transcribed from hand notes to pc docs.
 
Oddball

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I had to download a portuguese translator on my other PC. I've found references to 3 species of FW flounders, found in collection referrences, from peruvian waters. The 3 species are:
Achiropsis nattereri - lenguado - 9"

Achirus achirus - drab sole - 7"

Achirus mazatlanus - Mazatlan sole - 8"

I can't locate any pics of A. nattereri. A. mazatlanus exhibits a barred pattern that I don't see in the live or preserved flounders in my possession. A. achirus looks to be a good candidate to do some further searching on.
I'm about 3 hours overdue for my pain medication and I'm really feeling not that great. At any rate, here's a base for continuing the research. I'm going to kick back a while until the pain subsides.

achirusmazatlanus.jpg

Achirus achirus.jpg
 
Oddball

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Just glanced through a database of 792 freshwater species of fish IDd in Peru. I found 2 species of Trinectes. One is too small to be considered and the other looks to be a marine species IDd at a delta collection point. I did, however, find an additional FW species not listed in the earlier writeup: Hypoclinemus mentalis - lenguado - 8.5". This may be a reclassification of the aforementioned A. nattereri. Still checking. Achirus achirus still looks to be the best candidate.
Meds are starting to kick in. Can't trust what I'm likely to type. Later y'all.

Hypoclinemus mentalis.jpg
 
matty

matty

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Sorry to hear you don't feel so good Oddball. I had a check on Hypoclinemus mentalis and it's definitely not a reclassification of A. nattereri. Interestingly, both these species are freshwater only, and both have been recorded in Peru! The plot thickens. Unfortunately I can't find a pic of A. nattereri anywhere either. It does seems that Achirus achirus is not native to Peru though, suggesting that our Peruvian species is either H. mentalis or A. nattereri.
 
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