Salminus Questions for the Community

Andrew_Murphy

Candiru
MFK Member
Jul 31, 2007
19
31
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Boston, Ma
Hi Folks,

I have a few questions regarding Salminus growth, development, coloration, longevity, and breeding.

Currently I've a population of 45-47 S. brasiliensis that I've raised up from 8-12cm(sl) to 30-80cm(sl) over the past year. The vast majority of these animals are excelling, competing well, and are beginning to show all the hallmarks of sexual development/maturation yet aside from fins, opercula, part of the dorsal section I was expecting significantly more chromatic development by now in my few established super-males. Does anyone know when these animals typically reach sexual maturity and develop their famous gold coloration?

The animals are fed a well rounded diet of fish, insects, shrimp, mazuri gel diet, and supplemented astaxanthin weekly outside of the gel diet. Aside from intermittent phosphate spikes, water quality is great and stable. The pool is expansive, receiving natural sunlight, supplemented w/ metal halides.

Few general questions for experienced keepers:
What is the average lifespan of these animals in captivity? Has anyone here kept these to adulthood? Has anyone spawned these animals outside of their native range?

Maybe it's just me but there have been a lot of recent imports over the past 18 months of S. brasiliensis that have looked somewhat odd with juvenile headshapes more akin to S. franciscanus (including a few in my population) despite having the ray and scale counts of brasiliensis. Knowing that these animals are aquacultured is it possible that we have hybrid animals on our hands?

Appreciate the help!

Cheers,
Andrew
 

moe214

Goliath Tigerfish
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Oct 13, 2014
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How are you keeping them? All together? What size is the pool? You say they're Getting natural sunlight so is it outside or some sort of greenhouse being in MA or? Did you acquire them all at the same time? Thatd be a drastic difference in growth rates. Some questions which may help answer yours.

As far as their lifespan, I've not read of anyone keeping one till death of old age but I'd imagine in the range of 20 years maybe less maybe more, if kept properly. As far as sexual maturity I'm not sure, you can probably find that with a quick google search. As far as the coloration, we don't really know for certain as hobbyist what causes it, people have raised them to large sizes in aquariums and they're nothing like the go,d in the wild specimens. It's believed to be sunlight which you say they're getting, so maybe they just need more time. It won't happen over night. Frankies are said to be the ones farmed down in South America which is why we get them in the trade and rarely brassies. So as far as spawning brassies in the u.s atleast, I've seen nothing of that nature reported.

What you are seeing is usually just said to be mis-ID. Some even say they're captive bred, so can't be brassie one would think. But I suppose your theory is very possible, maybe we are getting hybrids. I have only seen one case where a true brassie had the head of a Frankie however.
 
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Andrew_Murphy

Candiru
MFK Member
Jul 31, 2007
19
31
46
Boston, Ma
Thanks for the reply!

Accessioned as a group, some minor discrepancies in size but nothing drastic, acquired from a reputable wholesaler in Miami who imported them as a group. Exhibit pool is 760,000L(200,000g) w/ ~20,000L additional in filtration. I've since relocated from MA, now living at a much lower latitude, the sunlight is slightly filtered by the roof but based on what I've seen with other teleosts here it should be enough to bring out melaniphores to full potential. Really hope it's just a matter of time and not genetics.

Leading up to the accession I did an immense amount of research on the genus and from what the formal literature says, S. brasiliensis and S. franciscanus begin getting color around 8", which I had initially taken as body color but it seems as though that was just isolated to the regions I mentioned before. The males are darkening up but it's wicked slow. Thanks so much for the insight!
 

Chicxulub

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I find this thread to be very interesting. Before I attempt to address some of your questions, might I inquire with a few in return? To what purpose are you working toward in keeping this group? In what are you keeping them? I'd imagine this group would require an absolutely MASSIVE setup to thrive.

As to the coloration. When I was preparing the Salminus care & ID guide, I spent a LOT of time trying to ferret out the answer to this riddle. Unfortunately, this does not appear to be something that has ever been addressed in the literature, but through my own research I can offer you some guidance on what I have found, but I consider it to be a personal anecdote and therefore insufficiently reliable to be included in my writing that I have "published" on this site.

Anyway, I have noticed a correlation to the coloration of the fish to the water in which they are living in the wild. Wild fish living in alluvial rivers with lots of sediment, poor visibility, hard water and relatively alkaline pH tend to be the least colorful. Those in clear water vary wildly; unlike alluvial rivers, it is hard to predict what the water conditions present would be. Those living in black water, which can be defined as moderately to heavily tanned, clear, soft and of relatively acidic pH tend to be quite yellow and handsome. It is my supposition that it is either the pH, hardness or combination of the two that produce the color. I'd wager that soft and acidic water would over the course of about a month produce the color you're looking for.

To further the veracity of my anecdote, I approached a similar situation with color in a genus in which I have extensive hands on experience for answers: Hydrocynus. I wished to explore the way that some Hydrocynus goliath would turn all black because, well, I wanted one lol. I ended up succeeding in making a fish black with heavily tanned, acidic, soft water, but due to finances and the difficulty of maintaining blackwater in a tank large enough for the fish without pH crashes, I abandoned the pursuit of answers, satisfied that I had seen a black goliath in person.

537512_10151471246909417_1853900646_n.jpg

As to scale counts, this is a subject which has given me quite a bit of consternation. In my counts of scales, I'm generally limited to counting between the dorsal fin and lateral line. In Lima and Britski (2007), there are mentions of counts between the dorsal fin and lateral line, but no mention of where exactly on the fish these counts were made. At the dorsal fin origin, there are typically 5-8 scale rows more than there are at the back of the dorsal fin. The only way that I have been able to consistently arrive at scale counts within the published limits for both species is to count scales at the most posterior part of the dorsal fin, as opposed to at the origin. Changing the counting location can very well "change" the result that the key to species coughs out.

There are quite a few people in the hobby who have managed to get these fish to similar sizes to yours, and to the best of my knowledge no one has ever succeeded in getting the particularly vivid yellows that wild type fish tend to have. The lack of wild type coloration is relatively common with South American fish.

The head shapes thing I included in the guide is a rough guideline, not a distinct diagnostic trait. There is a correlation between head shape and species, but it's not definitive, and I hope no one takes my "Diagnostic Traits for Hobbyists" as a definitive key, because this isn't my intention. If this is a problem, I'll change the wording. I don't really know if hybrids are possible within Salminus. I think the most likely explanation is that you have a personal selection comparable in size to what most importers see in an entire year. You're seeing th entire gamut of what's possible in the species.

That being said, in my opinion, the reputability of a commercial importer in the vast majority of situations doesn't really matter. You acquired these fish in 2015, and it wasn't until May of 2013 that the freshwater aquarium hobby as a whole even became aware that S. franciscanus existed. Before this point, everyone was trying to figure out the difference between S. maxillosus and S. brasiliensis, which are in fact the same thing with S. maxillosus being the junior synonym. Basically, what my quickly digressing diatribe is trying to say is that just because your importer said the fish were brasiliensis, that doesn't mean that they are.
 

KNH

Redtail Catfish
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My first thought is why would you attempt to keep so many? I'm a big fan of dorados and have kept several over the years.
 
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Andrew_Murphy

Candiru
MFK Member
Jul 31, 2007
19
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46
Boston, Ma
Hi Rob,

Thanks for your insight, really appreciate MFK's authority on the clade chiming in. These animals are in a public display, promoting conservation and wildlife education. The exhibit is 200,000g with ~5,000g in the filtration. As with any fishhead I'd love to breed them but just displaying the species to the general public is worthwhile enough. Today I've only just begun to see the precursory signs of courtship(similar posturing and swimming patters to brycon), but nothing from the females that indicates that they are sexually mature or gravid.

Water parameters
6.6-7.0 (usually 6.8 but unfortunately, due to other species within the collection, adjustments are 100% out of the question)
NO2 <.010
NO3 <10
NH3 <.10
System recieves influx of humic acid from falling leaflitter along with the diets of other inhabitants but the filtration applied removes a vast majority of what would likely contribute to the hormonal shifts sparked by tannins/humic acid
Phosphates will spike intermittently but nothing that would cause metabolic issues
System receives daily waterchanges w/ reconstituted RO


I'm away from my workstation right now, but I'll dig up the Brazilian paper where I got the scale counts for S. brasiliensis and S. fransiscanus. For future reference, formal scale counts performed dorsally are started from the anterior base of the dorsal to the lateral line and ventrally from the anterior base of the anal fin to the lateral line. Not sure if there may be some variability in how this is performed but this is how the MBL does it so I'll take their word for it haha.

The more I think about it, I wonder if the genetic variability in the founding stock of this population could attribute to this as well. We could even be looking at an issue with the holotype described(I mean look at how messy Symphysodon was up until 10 years ago, and that was 3 sp). Starting to look into papers on PCR done with S. brasiliensis and it looks like they do, infact, display a lot of genetic diversity.

Completely understand your point regarding the discrepancy with what is put on list by wholesalers and what arrives in your styro but I suppose that's part of the fun of ordering in bulk ;)

Thanks again for your time! Let me know if you find anything else out, I'll be mulling over what you've said and trawling papers for anything of interest.

Cheers,
Andrew

PS THATS A GORGEOUS HYDROCYNUS, would love to work with these one day
 

Andrew_Murphy

Candiru
MFK Member
Jul 31, 2007
19
31
46
Boston, Ma
My first thought is why would you attempt to keep so many? I'm a big fan of dorados and have kept several over the years.
Good question!

My primary concerns with displaying a group of these animals in the exhibit was conspecific aggression and interspecfic predation. I expanded upon what I've read on population distribution/gradients for the species to make sure that these animals can, in fact, cohabitate in large areas as adults while also drawing upon what small insight observing smaller relatives in the field might glean. I was pretty confident that would work out, and so far it has. There has been some aggression but the two primary targets of the supermales' aggression appear to have survived the worst of it.

Predation we were worried about, and honestly I still am, but the population has remained stable since introduction and the larger animals have not shown any overt predatory behavior in the past several months. At this point its just a matter of attempting to mitigate predatory inclinations and allow nature to take its course.
 

DB junkie

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^ Nope, I'd love to see some pics. I can't believe this thread has gone on this far without anyone demanding pics of said project?!?! This IS rediculous. Out with the pics!!!! Please!

IF you look at freshwwater rays they have the same mystery about color from wild to captive. "Blue" Motoros loose thier blue when put in a tank, Marbled Motoros often darken up, and captive Falkneri tend to be much darker then wild specimens.

I had heard light plays a part in the color of Dorado. The rays lack of color is said to be diet related, but some have suggested possibly lighting as well....

The "goldest" Dorado I ever raised really loved his Massivore pellets. Ate them from a very early age up through most of its life until passing at about 20".

Substrate sure does seem to affect the coloration of rays, wonder if it would darken Dorado? I've always kept mine on white - very bright substrate. Maybe black sand in a blacked out tank would make for darker more vibrant colors?
 
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