10G Tank Stocking

Byron

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On the glowlights/rummys and the gourami...the glowlights have more colour to them, and this could set the gourami off more than rummys might have done.  No way I can predict, just pointing out something.
 
Yes, I understand that the environment is very important! I do want to make my fish feel as comfortable as possible - I was only thinking of considering something like the glowlights if they were tank bred, in similar water to my tank - from what I've read, it sounds like whatever water a captive bred fish is raised in it will be adapted to, so it's better for them to mimic the environment that they've been raised in rather than the environment in which they would be found naturally - but I don't know how much that is true, presumably there are a lot of genetic adaptations which would take more than a generation or two to change! But I suppose even if it did, it would then effectively be an entirely unnatural fish, which is ethically questionable for many reasons - it just becomes a consumer product...
 
 
What I was trying to get at previously is that a species of fish which has evolved over thousands of years has a specific physiology and metabolism.  This is not going to be changed in a few decades for every species, though some may, sort of, but with so many other factors it may not be that alone.  The neon tetra today is a very weak fish, and succumbs to all sorts of issues.  Many believe the generations of commercial inbreeding has weakened the fish.  There is also the issue of differing parameters.  All of this likely plays into the problem.  Being maintained in similar water to that in which the fish was spawned/raised is sometimes beneficial, but certainly not always.
 
I suppose some species come from just one habitat, whereas others occur in multiple populations across a wider variety of habitats - although I don't think any tetras fall into that category. Even if they did, you would still presumably need to know which particular environment any wild caught stock come from to know their compatibility.
 
 
There are some generalities we can use.  We are talking soft water fish, so let's restrict this to the northern half of South America.  With few exceptions, the water will always be very soft; measurements have shown less than 1 d GH in all but a very few watercourses.  The pH can vary, from 3 or 4 up to the 6's, and even the 7's in again a very few areas.  So right away, we can say with considerable confidence that fish from this area need soft or very soft water.  The pH may vary, but I always suggest that the GH is the ore important; the pH will tend to follow the GH, and provided it is on the acidic side of 7 is not likely to be an issue.  The GH if it gets above being very soft or soft is another matter.  But we are being very general, there will always be exceptions.
 
Some species do indeed have a vast geographic range.  The Serpae Tetra, Hyphessobrycon eques, is one such species.  And this fish has been commercially raised for several decades now.  Dr. Stanley Weitzman noted in an article on this species in TFH (1997) that the aquarium fish we have differs from the wild fish (which themselves are very rarely encountered in the hobby) as a result of hybrids of fish from different geographical areas being used by commercial breeders in Florida and/or SE Asia.  Dr. Weitzman notes that this species even differs slightly in its colour/patterning in the wild populations.  This is one of the real dangers of commercial fish breeding--polluting the stock.  There has so far not been sufficient collections of this fish from the various geographical areas studied, to determine if there are sub species or perhaps distinct species within the complex.  The species Hyphessobrycon eques as described by science extends over most of the Amazon and Paraguay River basins, an immense area indeed.  This is not an exception.  While it is true that the vast majority of species in South America are restricted to specific geographic areas, sometimes one stream, there are several species found over a considerable geographic range.  
 
Carnegiella marthaethe black-wing hatchetfish, is one such species.  Phylogenitic analysis of collections from five (I think) different geographic regions--which are separated from each other naturally so the fish in one area can never come into contact with fish in the others--has determined there are at least three distinct lineages within the species.  Further study will be necessary to determine if these are in fact distinct species, subspecies, or simply geograhic variations.  The related Marble Hatchetfish, Carnegiella strigata, has a varied pattern depending upon its origin location, primarily with respect to the mid band across the keel.  At one time or another, five species were recognized, reorganized into two by Weitzman in 1960, C. strigata and C. vesca.  Gery (1977) recognized the very close physiological structure and modified these into subspecies as C. strigata strigata and C. strigata fasciata respectively, and noted that all species in this genus are polytipic, meaning that two or more distinct populations can be recognized within the species concept.  Weitzman & Palmer in Reiset al(2003) consider the one single species C. strigata.  There is one area where both forms occur in the same stream, and so far as is know, they do not cross-breed naturally but remain within their individual form.  This was a side observation, though it might tend to suggest they are not the same species, but more work is needed.
 
I don't know if there are any other medium sized rasboras that would work...I expect if I were to try anything else in there with him it would be best to go with a bottom dweller, something inconspicuous - I did wonder about otos, I think my lfs stock O. Affinis which according to planet catfish is suitable for my water - then again, it's too new a tank for something like that at the moment in any case. I suppose a more natural bottom dweller for the gourami would be some kind of loach, but of the few species that might be small enough for the space, I think most require softer water....sigh....I did discover one contender, the vietnamese zebra loach Y (or M, or N). cruciatus, which seems to tick all the boxes (might still be a little hard for it). I think my lfs might have some.... I assume the dwarf chain loach, A (or B). sidthimunki would be a little too big though. My substrate and planting look to be good for them too.
 
 
I've forgotten which tank this is now...if the 10g, it is too small for any of these loaches.  Micronemacheilus cruciatus is indeed a lovely loach; I had a group for several years, now only one remains, and they are very rarely seen sadly.  Mine is in with my group of Dwarf loaches, Ambastaia sidthimunki.  Dr. Maurice Kottelat began work on a comprehensive review of the loaches in 1980, and after more than 30 years the review was published on December 28, 2012. The banded species is returned to the genus Micronemacheilus as the lone (to date) species (and thus the type species for this genus) due to its very distinctive physiology. The subfamily is raised to family status.  The dwarf loach and a close relative rarely seen are the only species in Ambastaia.
 
Byron.
 
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chrisdenyer

chrisdenyer

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Thanks, that's interesting! I did think it would take rather longer for any fish to really adapt - and the inbreeding/hybridising problems makes sense. I wonder also if the breeding environments are particularly sterile that would affect the development of their immune systems as well, if they aren't exposed to any natural pathogens. 
 
On the loaches, I did wonder about tank size...my 45L has a 50x30 cm footprint, but I guess that's still on the small side for a decent group of M.Cruciatus (I discovered them through my lfs databank, which presumably means they stock them!). Alas, it looks like Gerald may just have that tank to himself! 
 
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chrisdenyer

chrisdenyer

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Well, my lfs' tetra stock is commercially bred in Singapore, so that's definitely a no go - they had a purple variation of the harlequin rasbora, so I decided to get 6 and see what happens. So far the gourami is completely ignoring them!
 

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