Nannostomus super red sp cenepa/amaya

[Kolykaf]

I was wondering if anyone has experience with these new (to the hobby) species. I’ve got the opportunity to acquire some at a very good price, but don’t want to invest a still considerable amount into fish that will prove too fragile to survive. I’m familiar with nannostomus as a genus and keep/have kept several species. I was hoping to put a dozen into my heavily planted (yet dimly lit) 75 gallon aquarium. I keep my Gh at 5-6, Kh at 1-2 so although it isn’t very soft, it’s been fine for all of my soft water fish (including wild caught). What I’ve read so far has led me to believe that they are rather hardy fish, but any first hand experience would be greatly appreciated.

 

[Back in the fold]

Calling @Byron !

 

[Byron]

I'm here. No first hand experience with this new species, but considerable experience with several other species in this genus. Following Weitzman and Cobb (1975), all pencilfishes are in the genus Nannostomus. There are currently 20 valid distinct species of which over the past three decades I have successfully maintained eight of them, including spawning (on their own) of several of these. I posted about this "Cenepa" in September of last year--that thread is linked below, it has some info on the genus and a video of this beautiful super red pencilfish.

Rio Amaya in the Rio Maranon drainage in Peru. As Oliver Lucannus mentions in the video, this is a blackwater watercourse which means the GH and KH are zero and the pH very acidic. My water for the species I kept was the same. The pH was down in the 4's or 5's, and the GH near zero (plant fertilizer provided the only minerals, and these so low as to be undetected with test kits).

When you say you keep the GH at 5 to 6 dH, does this mean you are adjusting the parameters somehow? This can make a difference, the method even more than the value resulting.

Extraordinary Pencilfish "species" Nannostomus sp. Rio Amaya

This photo was posted in the characin study group today. It is as yet undescribed so may or may not be a distinct species, but it is certainly stunning in its colouration. The fish was found in the Rio Amaya in Peru. I recall when Nannostomus mortenthaleri was first collected from the Rio...

www.fishforums.net

 

[Kolykaf]

Thank you, I have seen your previous post about them- along with everything else I could find in several google searches!
I use Seachem Equilibrium to remineralize R/O. I bring my water to TDS between 90 and 100 when performing water changes. In the time between water changes, the Gh and Kh rise a bit (around a degree or so). I assume it’s because of my substrate- which is supposed to be inert…In this tank, I currently keep N mortenthaleri (which I’d probably move to another aquarium upon getting the new fish) along with N digrammus and N eques.

 

[Byron]

OK. My advice is to stop the Equilibrium. I was persuaded by well-meaning members on another (plant) forum some years back to use this as I had/have zero GH/KH water. I was noticing calcium deficiency in the swords,so it made sense. The plants certainly improved, but then a marine biologist listed a couple of the minerals in Equilibrium and asked me if I really thought these were good for the fish. Obviously, they are not, so I stopped the Equilibrium. I found that Flourish Tabs provided the swords with what they needed, and Flourish Comprehensive Supplement the upper plants. And minimal dosage, better for the fish as the GH remained at 0.

If you have soft and very soft water species, consider that all of these in their habitats have basically zero GH/KH with an acidic pH. There are a very few exceptions. But if these fish have evolved to function at their most efficient in zero GH water, they do not need anything harder. The one tank I did the Equilibrium in, and for five or six years, did not have my most sensitive soft water fish like the pencils, but I would never use any chemicals in tanks with these fish.

I had over the years N. espei, N. rubrocaudatus, N. marginatus, N. mortenthaleri, N. eques, N.harrisoni, N. trifasciatus, N. digramus, N. unifasciatus, and N. beckfordi. None of these were combined in the same tank. Lovely fish.

 

[seangee]

I agree with @Byron on re-mineralsation. I keep a group of n.marginatus in RO water with nothing added and they are thriving there, along with cardinals and corydoras. Stick to easy, low light plants and the fish / fish food will provide sufficient minerals. I only add Flourish Comprehensive supplement (at half the recommended dose) to the tank in my signature.

 

[Kolykaf]

Thanks for your input. I’ve always added the Equilibrium for the plants’ benefit: the tank is very thick with both submerged and riparian plants and I’ve not wanted calcium/magnesium deficiencies to manifest. I’ll try weaning them off of the Equilibrium to see what happens…So, you’re not of the opinion that soft water fish have no problems acclimating to harder water? It is my understanding that, provided it’s done gradually, there are no ill effects on health or longevity. The only issue would be getting viable eggs from certain species- high mineral content makes them too hard for osmotic regulation/hatching. Interestingly, I’ve also been led to believe that harder water fish are different in that soft water does negatively impact them long term. I guess this made sense because I thought it seemed analogous to what I read in Diana Walstad’s book about aquatic plants. In short, soft water plants have evolved the ability to deal with mineral scarcity so they can survive where harder water plants cannot. When not faced with such scarcity though (ie. placed in hard water), they actually grow better. Hard water plants (which never evolved to deal with scarcity) by contrast, suffer in soft water. Obviously, plants and fish are different so it’s not a good analogy.

 

[Byron]

Thanks for your input. I’ve always added the Equilibrium for the plants’ benefit: the tank is very thick with both submerged and riparian plants and I’ve not wanted calcium/magnesium deficiencies to manifest. I’ll try weaning them off of the Equilibrium to see what happens…So, you’re not of the opinion that soft water fish have no problems acclimating to harder water? It is my understanding that, provided it’s done gradually, there are no ill effects on health or longevity. The only issue would be getting viable eggs from certain species- high mineral content makes them too hard for osmotic regulation/hatching. Interestingly, I’ve also been led to believe that harder water fish are different in that soft water does negatively impact them long term. I guess this made sense because I thought it seemed analogous to what I read in Diana Walstad’s book about aquatic plants. In short, soft water plants have evolved the ability to deal with mineral scarcity so they can survive where harder water plants cannot. When not faced with such scarcity though (ie. placed in hard water), they actually grow better. Hard water plants (which never evolved to deal with scarcity) by contrast, suffer in soft water. Obviously, plants and fish are different so it’s not a good analogy.

I cannot say much on the plant aspect. Obviously plants need certain minerals/nutrients to photosynthesize, and sufficient light intensity (spectrum factors in too) to drive photosynthesis. If these needs are met, the plants will grow. Some plants do better in harder water, Vallisneria for one, and this is because they assimilate carbon not only from CO2 but from bicarbonates. This species is native to the rift lakes for example. It will grow in soft water too, I did for many years, but I have no idea as to the balance in nutrients it was using.

Fish are a very different thing. And I certainly do not agree that they adapt to significantly differing conditions. They do not, most of them. Freshwater fish are very different from marine fish because each species of freshwater fish has evolved to function well in the specific parameters of its habitat. Marine fish live in the same parameter water across the globe, because the GH/KH and pH is basically the same. But not so with freshwater. Pure water, having 0 GH/KH and a neutral pH, occurs as condensed water in clouds. It does not exist anywhere on the face of this planet, because water is the universal solvent. As it falls, it assimilates substances, and once on the ground, it does the same with whatever it comes into contact with. Calcareous rock infuses the water with minerals and the GH/KH/pH is higher, whereas water falling in the Amazon does not have these minerals but organics, and the water remains very soft with an acidic pH. This is very general, a chemist could undoubtedly find flaws in this simplicity, but it gets the idea across.

So the fish that evolved in the Amazon stream has a physiology that needs very soft and acidic water. This is inherent in the species over thousands of years. There are many examples of species diminishing today due to the changes in their habitat waters. Hard water fish need the minerals, primarily calcium, to function at their best. Fish do not and cannot adapt except basically through evolution. The drip acclimation method is frowned on by very knowledgeable aquarists and biologists because it is useless. It takes fish weeks, months to "adapt" to fairly minimal changes. A study in Germany in the 1980's reported in TFH found that cardinal tetras (wild caught) had a lifespan directly proportional to the GH of the tank water. In soft and acidic water they lived beyond ten years, but in harder water the lifespan lessened as the GH was increased. Upon necropsy the reason for their death was calcium blockage of the kidneys. There is no logical reason to assume any soft water species is any different.

 

[seangee]

So, you’re not of the opinion that soft water fish have no problems acclimating to harder water? It is my understanding that, provided it’s done gradually, there are no ill effects on health or longevity.

I have seen a study on cardinal tetras that shows exactly the opposite, sorry I don't have the citation. Thanks @Byron just spotted your post so won't repeat it.
However I live in an area where the water is extremely hard and prefer soft water fish. Before I switched to RO I firmly believed the lifespan of cardinal tetras was 18-24 months and it cost me a fortune in replenishing stock. I was convinced they were just dying of old age. I switched after a chance dinner conversation with another fishkeeper (who I did not know). He assured me that his cardinals (we both kept similar fish, there were others) lived 6-8 years. We exchanged notes and the significant difference was that his water was very soft. Since switching I have rarely replaced any fish. I use cardinals as the example because it is highly improbably that any fry would ever survive in a community tank with the lights on.

Around the same time I was chatting to a fill in manager in my local chain store LFS, he was a hobby breeder and enthusiast. I was looking at the cardinals and he invited me to the quarantine area where they had recently arrived cardinals in soft water prior to hardening. The difference in colour was really striking. He assured me that this was simply due to being in the correct water. I can confirm that my fish now appear much brighter than in those days. He also told me that their mortality rate during the hardening process was over 50%. It was company policy to do this because its a hard water area (its cheaper to lose stock at cost - and you can build this into your margin, than refund dead fish at retail, and of course there is reputational damage if that many of your sales die!). So their acclimatisation process was simply to sell whatever survived the transition.

I don't keep records but it would not surprise me if my average lifespan is now 6-8 years or more.

 

[Kolykaf]

All of what you say makes perfect sense, and it’s what I thought when getting into the hobby 10 years ago. Why wouldn’t a fish keeper try to mimic the conditions of a species’ natural habitat as closely as possible? There’s just so much conflicting information out there with people claiming success with parameters sometimes quite different from the expected. How does one argue with what seems to work for others? Of course, we’re not always getting the full story: keeping a fish alive for 1.5 years is very different from keeping it alive for 8 years… One of the more interesting theories I’ve heard is that soft water fish die in captivity not because of harder water directly, but because they are subjected to a host of bacteria which are not found in the low ph of their native waters. I made sure to get a UV sterilizer just in case.

 

[Byron]

All of what you say makes perfect sense, and it’s what I thought when getting into the hobby 10 years ago. Why wouldn’t a fish keeper try to mimic the conditions of a species’ natural habitat as closely as possible? There’s just so much conflicting information out there with people claiming success with parameters sometimes quite different from the expected. How does one argue with what seems to work for others? Of course, we’re not always getting the full story: keeping a fish alive for 1.5 years is very different from keeping it alive for 8 years… One of the more interesting theories I’ve heard is that soft water fish die in captivity not because of harder water directly, but because they are subjected to a host of bacteria which are not found in the low ph of their native waters. I made sure to get a UV sterilizer just in case.

Bacteria is a relevant factor generally, but not the primary reason.

I write frequently on the plethora of mis-information in this hobby, thanks to the internet. We have access to incredible sources provided we know which ones, but without knowing the information can be worthless or more importantly downright dangerous. I have been doing research long enough to know the reliable sites, and these and only these do I trust.