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Blackwater for Featherfin catfish?    & circ., Af. biotope...     10/17/16
Hi WWM experts! I'd like to thank you in advance for any information you may be able to provide.
<Most welcome.>
Quickly I will state that about 18 months ago I started my first tank.
Unfortunately, I was stricken very quickly with MTS (I guess Multiple Tank Syndrome and Malaysian Trumpet Snails would both be relevant in the context of that statement).
<Heh!>
Anyhow, at one point I had 15 medium to large tanks operating all with different water chemistry/biotopes/species etc. in my (very small) home.
Needless to say, it was like a full time job.
<Understood. Some folks have "fish rooms" and I'm totally blown away by their dedication and hard work. But for me, two tanks is about right. One for a general community, and one for something special. After that, extra tanks always seem to be a chore!>
I have made many mistakes and more recently enjoyed some great successes.
<Cool.>
Through careful and conscientious rehoming, I have since reduced my tank collection from 15 to 5 tanks but will soon be aiming for only 1.
<Understood.>
My question is this... I would like to take my 2 Featherfin catfish out of the 75 gallon rift lake tank that they are in and place them in a 125 gallon tank with a juvenile Oscar. These will be the only tank inhabitants and it will be filtered using 4 x canisters which are rated at 280 gph.
<Slightly confused here. The Featherfin Catfish, Synodontis eupterus, is a soft water fish. While it certainly will live in hard water, it doesn't need it. On the other hand, there are Rift Valley Synodontis species, such as Synodontis multipunctatus, that need hard water conditions. If this catfish is Synodontis eupterus, then yes, it'll be absolutely fine in
whatever conditions your Oscar is kept in. They have very similar requirements, and Synodontis eupterus is peaceful enough but big enough to cohabit with Oscars. They get along very well, both being (comparatively speaking) gentle giants. Just ensure they have enough space and in particular caves they can call home without squabbling.>
I would very much like to set this up as a very dark blackwater tank.
<Nice. Just not *too* soft. I'd not go below, say, 2-3 degrees dH because the pH often becomes unstable in very soft water.>
I have well water with moderate hardness and pH (I'm sorry I don't have the exact numbers currently, but it is not extremely hard and the pH out of the tap is about 7.4). I have consistently used a small amount of salts and ph
buffers in the rift tank, bit nothing dramatic.
<More than likely mixing your tap water 50/50 with RO or rainwater will produce something that'd be perfect for these two fish, around 10 degrees dH, pH 7.>
Other than poor stocking mistakes (Mbuna with peacocks and haps mostly), the tank seems to run well (minus my evil blue dolphin moorii), I even had 3 successful zebra fry make it to juvenile stage and are free swimming now!
Anyway, I would like to keep my two Featherfins (they are my favorite fish) and I am rehoming the rest of the inhabitants. I would very slowly and carefully acclimate them into the 125 which would be a new (fully cycled) setup. I want to recreate a very dark blackwater look without causing pH fluctuations.
<Do read up on this. I'd have you start off here...
http://www.wetwebmedia.com/FWSubWebindex/fwsoftness.htm
But much else on the topic on WWM and the Internet/books. While soft water is often seen as the ideal, it actually isn't necessarily the optimum for easy fishkeeping, and few fish need genuinely very soft water. Often slightly soft to medium hard, around neutral water works perfectly well, and the dark colour can be added to the tank using blackwater extract
without dramatically affecting pH.>
I know that because my water is not soft, that there are products (blackwater extract) and/or methods (peat or Indian almond leaves) than can get me the look and have the natural carbonates in the water cancel out the acidifying and softening effect.
<In very hard water, none of these (blackwater, peat, or leaves) will have much impact on hardness without using them in MASSIVE quantities.>
But which method(s) is the best to keep the water stable but give me the darkest look?
<See above. Use blackwater extract for cosmetic colouring of the water, but mix the well water with RO or rainwater to lower the hardness as necessary.>
There will be plenty of driftwood in the tank as well, but it is all pretty much cured at this point so won't be adding many tannins. Also, I know that this is not the "natural" environment for my Featherfins but I feel like they would enjoy the darkness and from what I have read, they come from somewhat dirty and muddy environments in relatively varied areas of the same region. Would leaf litter on top of soil help in this tank (or disrupt the pH or be too messy?) or would just a sand substrate and a tannin mixture be better?
<Oscars are shovellers, and will make a complete mess of any soil in the tank. Better to go with gravel or slate chippings that they can't move about too easily. Decorate with your bogwood and rocks, and a few plastic plants if you want. Floating plants are a plus, and the Oscar will even eat some of them if it gets hungry (they're a bit more omnivorous than often supposed).>
Lastly, and most importantly, do you think that this would be a comfortable and enjoyable environment for them?
<Yes; Oscars and large, docile Synodontis work very well.>
I apologize if any or all of this seems scattered or unfocused. Since this will be my only tank, I want to take all that I have learned and make it the best environment I can for these 3 fish (unless I decide to get a couple more Featherfins to add). Thanks again, I look forward to your response!
<Good luck, Neale.>
Re: Blackwater for Featherfin catfish?       10/17/16

Thank you Neale for the quick and informative reply.
<Welcome.>
The reason I have the Featherfins in harder water is only because they are currently in a rift lake setup. I'm glad to know that they will thrive in softer water.
<Good.>
You brought up a great point that I overlooked regarding the Oscar, because this will be my last remaining tank, I really would like to have a beautiful display without the constant destruction which would be caused by the Oscar.
<Not destructive if kept with things they cannot move. Big rocks for example. Can look very attractive in such settings.>
So as most of us do on a regular basis, I hit the web trying to glean the absolute best and most interesting stocking list for this setup. Many many hours later I think I have settled on a large shoal of Exodon.
<Yikes!>
I find that their presence in the tank as well as the spectacle they create at feeding time will definitely not keep me bored and allow for an impressive shoal in a 125 gal. I know that they are nearly as vicious as it gets, so I wouldn't want to subject my Featherfins to torture or stress.
<Indeed. A non-starter combining them. Exodon paradoxus will strip the fins away in no time.>
I have read many accounts of people saying that they absolutely cannot have any tank mates and have read a lot of testimonials saying that since they are scale eaters, any fish in the tank that aren't shiny and have no scales they will ignore.
<Possibly... but not worth risking. Since these fish are aggressive towards each other, you want to keep as many as practical, at least 12, and the more you keep, the better the chances they'll live together happily. If by some chance your aquarium has space for a tankmate, then you are MUCH wiser using that extra space for MORE of the Exodon paradoxus.>
Obviously the Featherfins fit the latter description perfectly.
<Still live food for these characins.>
I do however don't want them to stay in hiding either, as in the rift tank they are out of their caves a good percentage of the day. I would also be keeping the Exodon extremely well fed with market shrimp, fish flesh, earthworms, possibly gut loaded guppies, etc.
<Not Guppies. That'll only train them to see "fish as food", which 99% of the time will be other Exodon. Shrimp and mussel used sparingly (rich in thiaminase). Good staples include quality flake food, carnivore pellets as they grow bigger, and insects of various kinds, such as bloodworms.>
So what are your thoughts about these potential tank mates?
<Nope.>
Also, since I will have the 4 canisters with approx. 1100gph on the tank, do you think a shoal of 60 would be too much (or too little) in the 125 gal?
<I'd allow at least six gallons per Exodon, given their adult size (15 cm/6 inches potentially, though usually around half that under aquarium conditions). So something around 20-25 specimens in 125 gallons is nearer the mark.>
Thanks again in advance!
<Most welcome. Neale.>

Re: Blackwater for Featherfin catfish? System water circ. mainly        11/5/16
Hi Bob, thanks for the advice and encouragement. Yes I was referring to the eupterus.
<Beautiful, intelligent animals>
Of the large variety of fish I have kept, these guys are my favorite, I absolutely love their personalities and I see them out of their caves almost all day, unlike many of the experiences I have read from others who keep them. Thank you so much for the gyre suggestion! I did read the Jake Adams' essay that you linked to as well as at least a dozen
others and plenty of discussion about a gyre setup here on WWM.
Unfortunately, using "gyre flow tank" or any similar phrasing in a search engine results in endless pages of discussion about the Maxspect Gyro product. Once I manually omitted the company's name from the search results I was able to find more, although not as much as I expected, and all of it being discussed in marine tank usage. There was plenty of great information though, although there are so many conflicting ideas and vague descriptions of setups that it has me confused. Much talk in freshwater discussion is resolute and unwavering in the importance of surface agitation for gas exchange, almost zealously. But in a gyre system, set correctly, wouldn't the massive water volume movement be enough to aerate the water sufficiently without having to specifically be pointing ph's up towards the surface or spray bars across the surface?
<Yes it does help with oxygenation, release of CO2... And I WOULD set the pump/powerhead discharges therefore near the surface....>
I have attached a photo of a gyre setup that I have found that looks the simplest for me to understand. In the photo, I can easily see how the water travels lengthwise down the back and front, but is the water movement losing
efficiency when it hits the short sides (in my tank 24") and becoming somewhat chaotic but then somehow picking back up as it hits the next long side?
<Yes>
It looks mostly like two currents in opposite directions, although I understand the placement of the "divider in the middle is what helps curate the circular pattern.
<Actually, the density of the water (some 784 or so times more than air) and the sp3 hybridization of H20 (its "stickiness") greatly discount the need/function of a divider here>
But, should 2 more (one on each end) additional ph's be placed at the bottom of the short sides angling up to push the water more efficiently across back to the lengthwise ph's, thereby creating a more continuous circuit instead of relying on the water to behave appropriately when hitting a short side?
<Will/would help, but not necessary. I encourage you to do some simple experiments... perhaps with food coloring, a pipette to place... with the tank just filled with water...>
Or should I somehow create a curve on the two corners that the ph's are pointed to, to make the water sweep
through the turn instead of hitting a 90 degree angle and losing momentum by attrition?
<Just straight in will work... but try/see for yourself>
I'm considering changing the initial design of an alcove theme to compensate for the gyre setup, if my thinking is correct, breaking up the water flow like that would pause it's momentum in the circuit and thus losing the circular flow around the tank?.
<? Mmm; I'd place the pumping mechanisms in two opposite corners, near the surface.... >

So I will be thinking about a centered large piece of driftwood to help create the vortex current around it, sort of a freshwater version of the centered live rock setups I saw in marine gyre tanks. I've attached a few photos of the piece I am set on buying, if you think it would work, otherwise I can keep looking.
<Tis a beauty>
It's measurements are 30"H x 18"L x 15" W as seen from the photo standing straight up. I'm not sure if it is too big or has enough natural caves or hideouts for the eupterus and the Steatocranus at the bottom? Although there is a spot in the middle I could see the bichir claiming. I have attached a few photos of different angles of the piece, and although it is quite impressive, it is expensive and I will have to have it shipped from Texas to New York which will be even more expensive. I would like your advice on if this is the centerpiece of all centerpieces, in the context of the specific tank I've been describing of course, or if you think that it would be better to create a sort of stockpile of stones in the center
instead?
<Mmm; I prefer (this piece of) wood>
If I do go for that piece of wood, do you think a tall setup reaching to the very top of the tank sticking out 6" above the water's surface with Anubias attached in clumps over the whole thing (better aesthetic) or lengthwise (possibly more function for the fish or the gyre flow continuity?) would work best?
<I'd do the set up w/ the wood, the powerheads, pumps (look at EcoTech's line here)>
My last bit of discussion will be about filtration. I have 4 x Hydor 350 canisters, they are rated at 280 gph. I plan on using all 4 but having the water fall straight down from the return hose, which won't create the surface break of a spray bar or a lily pipe fitting, but since the water will be 6" below the surface of the tank I don't know if I could deal with the additional noise that an adapted return fitting would cause when hitting the water surface. My idea was to place the intakes grouped side by side in the middle of the back pane. What, if any, effect does this have on the gyre rotation?
<Mmm; would have to try/experiment to see. Right off, my feeling is "not much"... if using the spray bars discharging in the flow of the gyre, perhaps a bit; maybe not discernible at all>
Will it break it halfway along the back length, therefore not allowing enough momentum to reach the
opposing corner and "turn" before catching the next long pane propulsion?
<Again, I'd either elbow the flow to join w/ the powerhead induced gyre, or use the spray bar discharges placed vertically to do the same>
Also, Instead of filling each canister with a tray of foam, a tray of floss, and, 2 trays of ceramic rings, could I just fill one canister full of foam, two canisters full of biomedia, and one canister full of floss, effectively making my filter maintenance infinitely easier, or is that just wishful thinking?
<Not just wishful. DO look into Siporax, Ehfi-Mech and such as a permanent biomedia>
If you would also look again at my stocking and see if this driftwood centerpiece gyro flow tank would be problematic for the amount or variety of fish that I listed?
<Unless you get/use HUGE flow powerheads, submersible pumps, there will not be "that much" "grand" gyre effect. If anything, the Pantodon might "hide out" near the submersible wood>
I am perfectly fine with understocking the tank if it is the best interest of the inhabitants.
Especially since there will be far less hiding spots, or more contested ones, in this setup. Although there will be a dense planting of water lettuce on the surface. Now that I mention that, will the gyre flow be turning at the top and causing the lettuce to all clump in the middle?
<Likely so>
Is this much movement bad for them and thus the Pantodon and Ctenopoma who will need the roots fairly full and stationary or am I confusing circulation pattern with flow rate?
<Don't think either will be problematical here>
I am very interested in your thoughts because I tend to over think, and I trust the value of your opinion and experience
over my own when it comes to something as serious as creating the perfect environment for the health and well-being of the fish in my care.
Thanks!!
<Welcome. Bob Fenner>

Re: Blackwater for Featherfin catfish?   Back to Neale      11/6/16
Hi Bob, thanks for the advice and encouragement. Yes I was referring to the eupterus. Of the large variety of fish I have kept, these guys are my favorite, I absolutely love their personalities and I see them out of their caves almost all day, unlike many of the experiences I have read from others who keep them. Thank you so much for the gyre suggestion! I did read the Jake Adams' essay that you linked to as well as at least a dozen others and plenty of discussion about a gyre setup here on WWM.
Unfortunately, using "gyre flow tank" or any similar phrasing in a search engine results in endless pages of discussion about the Maxspect Gyro product. Once I manually omitted the company's name from the search results I was able to find more, although not as much as I expected, and all of it being discussed in marine tank usage. There was plenty of great information though, although there are so many conflicting ideas and vague descriptions of setups that it has me confused. Much talk in freshwater discussion is resolute and unwavering in the importance of surface agitation for gas exchange, almost zealously. But in a gyre system, set correctly, wouldn't the massive water volume movement be enough to aerate the water sufficiently without having to specifically be pointing ph's up towards the surface or spray bars across the surface? I have attached a photo of a gyre setup that I have found that looks the simplest for me to
understand. In the photo, I can easily see how the water travels lengthwise down the back and front, but is the water movement losing efficiency when it hits the short sides (in my tank 24") and becoming somewhat chaotic but then somehow picking back up as it hits the next long side? It looks mostly like two currents in opposite directions, although I
understand the placement of the "divider in the middle is what helps curate the circular pattern. But, should 2 more (one on each end) additional ph's be placed at the bottom of the short sides angling up to push the water more efficiently across back to the lengthwise ph's, thereby creating a more continuous circuit instead of relying on the water to behave
appropriately when hitting a short side? Or should I somehow create a curve on the two corners that the ph's are pointed to, to make the water sweep through the turn instead of hitting a 90 degree angle and losing momentum by attrition? I'm considering changing the initial design of an alcove theme to compensate for the gyre setup, if my thinking is correct, breaking up the water flow like that would pause it's momentum in the circuit and thus losing the circular flow around the tank?. So I will be thinking about a centered large piece of driftwood to help create the vortex current
around it, sort of a freshwater version of the centered live rock setups I saw in marine gyre tanks. I've attached a few photos of the piece I am set on buying, if you think it would work, otherwise I can keep looking. It's measurements are 30"H x 18"L x 15" W as seen from the photo standing straight up. I'm not sure if it is too big or has enough natural caves or hideouts for the eupterus and the Steatocranus at the bottom? Although there is a spot in the middle I could see the bichir claiming. I have attached a few photos of different angles of the piece, and although it is quite impressive, it is expensive and I will have to have it shipped from Texas to New York which will be even more expensive. I would like your advice on if this is the centerpiece of all centerpieces, in the context of the specific tank I've been describing of course, or if you think that it would be better to create a sort of stockpile of stones in the center instead? If I do go for that piece of wood, do you think a tall setup reaching to the very top of the tank sticking out 6" above the water's
surface with Anubias attached in clumps over the whole thing (better aesthetic) or lengthwise (possibly more function for the fish or the gyre flow continuity?) would work best? My last bit of discussion will be about filtration. I have 4 x Hydor 350 canisters, they are rated at 280 gph. I plan on using all 4 but having the water fall straight down from the return
hose, which won't create the surface break of a spray bar or a lily pipe fitting, but since the water will be 6" below the surface of the tank I don't know if I could deal with the additional noise that an adapted return fitting would cause when hitting the water surface. My idea was to place the intakes grouped side by side in the middle of the back pane. What, if
any, effect does this have on the gyre rotation? Will it break it halfway along the back length, therefore not allowing enough momentum to reach the opposing corner and "turn" before catching the next long pane propulsion?
Also, Instead of filling each canister with a tray of foam, a tray of floss, and, 2 trays of ceramic rings, could I just fill one canister full of foam, two canisters full of biomedia, and one canister full of floss, effectively making my filter maintenance infinitely easier, or is that just wishful thinking? If you would also look again at my stocking and see if
this driftwood centerpiece gyro flow tank would be problematic for the amount or variety of fish that I listed? I am perfectly fine with understocking the tank if it is the best interest of the inhabitants.
Especially since there will be far less hiding spots, or more contested ones, in this setup. Although there will be a dense planting of water lettuce on the surface. Now that I mention that, will the gyre flow be turning at the top and causing the lettuce to all clump in the middle? Is this much movement bad for them and thus the Pantodon and Ctenopoma who will
need the roots fairly full and stationary or am I confusing circulation pattern with flow rate? I am very interested in your thoughts because I tend to over think, and I trust the value of your opinion and experience over my own when it comes to something as serious as creating the perfect environment for the health and well-being of the fish in my care.
Thanks!!
<<I'm a bit confused why you want turbulent flow here. The Ctenopoma and Pantodon will object to this, strongly! Ctenopoma are pool, swamp and sluggish river fish. Pretty much anything that gulps air can be assumed to prefer slow-moving bodies of water, else that adaptation would be redundant. Air-breathing fish that become adapted to fast water
(mouthbrooding Bettas, Candela spp.) tend to gulp air less frequently when compared to the standard-issue obligate air-breathers. As for Pantodon, they aren't strong swimmers. Most Synodontis are riverine fish, but may be more or less adapted to strong water currents. Broadly, those species with "long and low" bodies like Synodontis angelicus and Synodontis brichardi) are the ones that want/need strong water currents and plenty of oxygen.
Those Synodontis with rounder bodies (like Synodontis nigriventris and Synodontis eupterus) are more suited to deep, sluggish water lakes and river pools away from the rapids the preceding species favour. I'd be focusing on turnover, rather than turbulence, and going for a large volume of turnover but at relative low pressure. A big canister with a spray bar, for example, or multiple air-powered sponge filters, or whatever suits. In a tank with epiphytic and floating plants, even a classic undergravel filter can also work well, providing large amounts of filtration without requiring using several smaller powerheads, so evening up the water current around the tank. Cheers, Neale.>>
Re: Blackwater for Featherfin catfish?      11/6/16

Hi Neal, thanks for the info. Yes I would be happy to change my stocking list. I got a lot of the info from
http://fish.mongabay.com/biotope_african_rivers.htm
<A great, if old, website; not sure how regularly it's updated these days.
But in any event, do bear in mind the concept of an "African river" is about as vague as talking about an "American accent". There are all sorts of rivers in Africa, and some of them are literally thousands of miles in length. In some parts they'll be fast, in others slow; sometimes deep, sometimes shallow; sometimes running through rainforests, sometimes cutting across grasslands... there really isn't one African river biotope, but many, and the fish adapted to one part of the river won't be found in another.>
My stock list actually came from the idea of a side stream, but once I started reading about gyre circulation I am 100% positive this is the system I want to setup. I did mention at the end that I may be confusing circulation pattern with flow rate.
<Possibly, but at the same time, in a tank below 100 gallons in size, there may be little practical difference between having gyre-like circular water movement versus turbulent flow from one or two powerheads/canisters. Bear in mind that a marine aquarium "gyre" pump is basically designed to provide a wide "slice" of water rather than a narrow "spurt" like you get from a traditional pump. On top of that, gyre pumps can pulse this slice, replicating, in a limited sort of way, the movement of waves or currents.
In theory, there's nothing wrong with applying this to a freshwater system, particularly something like a Great Lake biotope. But in reality, freshwater streams and rivers tend to be comprised of fast moving water areas with slower areas nestled in between, and freshwater fish will exploit one or both of these depending on their ecological niche. Loaches,
for example, commonly rest in the slow-moving areas under rocks and wood, but dart out into the open, faster water areas to graze on algae and invertebrates. Relatively few aquarium fish are adapted to living their entire lives in strong water currents -- such fish would actually find the contained aquarium lifestyle rather difficult to adapt to.>
I was just concerned with getting the water around the corners to continue the gyre unimpeded but don't necessarily desire a forceful rapid rotation, just a continuous controlled one.
<See above; some relatively slow moving pockets of water are actually realistic, even necessary. For sure you don't want dead areas, but any decent filtration system should prevent this.>
As I mentioned I am willing to change the stocking. I had thought if I did the gyre toward the middle to bottom of the tank the surface vegetation wouldn't really be interrupted as much, especially with the water circulation hugging the wood and keeping its circular motion.
<Few plants will tolerate really strong water movements; Vallisneria are obvious choices, perhaps Anubias. Some careful selection will be necessary.>
Would you be willing to make some stocking suggestions for me? I am assuming the Debauwi and Congo tetras would be fine as well as the Steatocranus?
<Steatocranus is an interesting genus. While usually okay, some male specimens of Steatocranus casuarius can be extremely aggressive. Approach with care. Nanochromis is an option, but these are soft water cichlids and quite delicate. Riverine (as opposed to lacustrine) Lamprologus might be a better bet, but alas, are not too widely traded. Lamprologus congoensis is about the only one you see fairly regularly. Unless the water current was very high, some of the Tilapiines might actually work nicely, though their behaviour varies a bit. In big tanks I've never had trouble with
singletons, Tilapia rendalli in particular being especially attractive.
Tilapia joka (or Coelotilapia joka) is generally considered among the more reliable Tilapiines for home aquaria. It's quite small (under 15 cm/6 inches) and nicely marked. It's a riverine herbivore, and should handle fairly strong currents without problems, but do ensure some suitable resting spaces, such as caves.>
How about the bichir?
<The really big species are riverine, though favouring sluggish rather than turbulent water flow, and tend to be found in the large pools and lakes rather than, say, riffles and rapids. The smaller species are basically swamp-dwellers, and should be housed accordingly.>
That driftwood has a perfect home for him. And what about the kribs?
<River-dwellers for sure, but shallow, slow-moving rivers in rainforests rather than open areas with fast water flow (where Nanochromis, in particular, replace them).>
if the Ctenopoma and Pantodon would be miserable I won't include them.
But I really just want the precise flow pattern, not necessarily the speed....
<Don't over-complicate! Cheers, Neale.>
Re: Blackwater for Featherfin catfish?      11/6/16

Hi Neale, thanks again for the great advice.
<Welcome.>
It's important to mention that the photos that I sent Bob of the centerpiece of wood will fill up the whole middle of the tank being it is 18"L x 15"W x 30"H with a lot of natural caves holes and pass-through's and the tank is a 150gal tall so 48"L x 24"W x 30"H. The idea was to place this large driftwood vertically in the center with some smooth stones
gathered around the base for a few additional cave areas. Clusters of Anubias would be attached creeping up the entire height.
<Sounds nice.>
The water level was going to stay 6" low for the Pantodon with a full covering of dwarf water lettuce and 6" of the wood above the waterline to a nice effect. My idea is to set it up how a marine reef tank might create a gyre with a center grouping of live rock, but instead, a large driftwood structure. Wouldn't this, combined with the pumps being angled along the glass create an open swimming area out of the flow through the middle of the tank?
<Should do. But much the same affect, and more controllable, might be using plain vanilla powerheads dotted about the tank. The Hydor Koralia magnetic powerheads spring to mind for big tanks; for smaller tanks, anything should work, though the Eheim Aquaball powerheads are probably the best in terms of value and reliability.>
I somewhat understand the theory of water pulsing and wave creation and directional changing flows for corals and reef inhabitants in a marine tank. But I'm not trying to create that effect. I want a truly laminar flow, just circular and unidirectional.
<Ah, then powerheads would be much simpler.>
One of the things I dislike about my previous and current setups has been water flow accuracy or circulation pattern consistency. I mostly would set the spray bars at the top against the back and flowing towards the front, rotating sections at slightly different angles to get some movement towards the bottom and making sure to spray some along the surface. What I don't enjoy about this is that the water current becomes randomized once it hits the front glass or a structure in the tank and just goes about in whichever way it pleases.
<Yes, though this depends on the intensity of the water current. Strong the outflow current, the longer it'll take before it becomes turbulent. But do understand that randomised, turbulent flow distributes oxygen evenly. A fixed current will take oxygen where it goes, but the static pockets of water will receive less oxygen (and potentially heat, for that matter).>
This idea of the laminar gyre would be opposed to other riverine setups I have seen as closed systems with pumps at one end and intakes at the other to create a lengthwise laminar flow. But anything that it hits structure-wise on its way from one end to the other, to me seems like it would again cause a random or chaotic circulation pattern.
<Do read up on these; have been used successfully for loaches and hillstream biotope tanks; see here:
http://www.loaches.com/articles/river-tank-manifold-design
Requires some careful plumbing, but very effective.>
It seems as if you and Bob are in some disagreement about this setup, which is awesome to me because, that is what I love about this hobby, the discussion and knowledge seeking and sharing of thoughts and ideas to create new and interesting experiences. I have thought of a stagnant very slow moving blackwater setup with leaf litter and such, but am very confused as to how to aerate the water and get CO2 exchange to be enough with such minimal vegetation.
<You don't need to. Bichirs and Ctenopomas are air-breathers. Pantodon stay close to the surface, were oxygen level is best. Bottom dwelling characins and barbs from sluggish streams are slow-moving, have low metabolic rates and limited oxygen demands, so don't need very high oxygen levels compared with danios or cichlids from clearwater streams. See, evolution has taken care of this for you!>
In some strange way I am trying to make things less complicated by creating, from the start, a consistent and easy to maintain system, lessening some of the variables that occur in a "normal" setup. But I know nearly nothing compared to you guys, so if this is a dumb idea then it's a dumb idea. If I were to create something like this, what could live in it
and be relatively happy living in and around this large driftwood structure as well as the root system of the surface vegetation, besides the Lamprologus or Nanochromis, which I'm just not interested in keeping?
<Classic Synodontis companions including Xenopterus, Polypterus, Distichodus, most of the larger Mormyridae, schools of medium-sized characins like Alestes and Phenacogrammus... all sorts, really. All these appreciate steady, but not turbulent, water flow.>
Keeping in mind that this is a 150 tall with the width being half that of the length and a large center structure. The whole reason that this search path started for me is that my 2 eupterus coexist beautifully on separate sides of my 75gal and only fight when trying to swim in the current created by the spray bar. They will swim in it facing away from me all day until one wants to kick the other out. The female always wins. I don't mind being told I'm an idiot so if my thoughts on this are skewing idiotic, please feel free to tell me haha. I've reattached the photos of the wood centerpiece that the gyre would circle around. I'm looking very forward to reading your reply. Thanks so much again for taking the time to discuss this with me!
<Most welcome. Neale.>

Water current / filter power / How much is enough, how much is too much and more?   3/1/12
Hello,
<Hello,>
My girlfriend purchased a Top Fin Aquarium kit and stand. The aquarium is 30"W x 12"D x 22"H; 37 Gallon, and it came with a Top Fin Power Filter 40 (supposedly 200 GPH). We have set the aquarium up (2 large ornaments, Black Sand in the bottom).
We purchased 6 Neon Tetras to cycle the aquarium (not the best fish choice for cycling I now know, but we live and learn). They have been living in the aquarium for just a couple of days now.
<I see.>
I know top fin isn’t the best brand, and I know we will need to add some plants and hiding spots for the fish, but before we get to that I had some more basic questions.
I am having trouble finding information about water flow (Water current) in a freshwater aquarium.

<Yes…?>
One of the decorations had an air stone in it, but the air begins about ½ way up the aquarium (It’s a dragon standing on its back legs, spewing bubbles from its mouth). I mention this only to say there are currently no bubblers at the bottom of the tank (nothing down there to help move/stir up the water).
<For all practical purposes, ignore air-powered toys. They do very little of use. At best, they help with circulation to a minor degree, but unless you have an extremely powerful air pump, the amount of water being moved is trivial. Contrary to what beginners imagine, the bubbles themselves don't add oxygen to the water. In short, ignore them. Unless you're using an undergravel filter, make all water turnover estimates on the filters alone.>
The Top Fin 40 HOB Power Filter creates a fairly significant “Downward Current”, on one side of the tank. So far the Tetras seem to be completely avoiding this “Downward Current” of water… and when they are in the corner of the aquarium (near one of the decorations seeming in a spot that is somewhat sheltered) they seem to be swimming rather hard, just to stay stationary. I’m not sure if this is standard fish behavior, or if they really have to swim hard to stay stationary because of the water flow.
<Cardinals prefer low water current.>
Also, I noticed that one of the fish flakes I fed then the other day is sitting still in the dead center of the aquarium floor, so obviously the current isn’t too intense, otherwise I would think the flake of fish food would move around the bottom of the tank…
<Correct.>
(Perhaps it’s just next to a raised area of sand, and therefore safe from the current).
I have been searching and reading for the last 5 hours about water currents in fresh water aquariums, but I’m not finding a lot of information.
<Hmm…>
Here are some of my unanswered questions:
1.       Is the Downward water current created by a 200 GPH filter too much for small fish (I can turn down the flow rate if necessary)? I would assume that the manufacturer would provide the correct equipment for success in an aquarium “Kit”, but to be honest I don’t have that much faith in most manufacturers….
<For small, non-fast water fish, a turnover rate 4-6 times the volume of the tank is adequate. So a 200 gallon/hour filter would be about right for a 50 gallon tank (at 4x the volume of the tank/hour) up to about 33 gallons (for 6x the volume of the tank/hour). Bigger fish, messier fish, or species like loaches that want high water current species will need more turnover, 6, 8 or even 10 times the volume of the tank per hour.>
2.       Is the current produced by the filter insufficient to reach all areas of the tank (30"W x 12"D x 22"H)?
<This is about 34 gallons in size; so see above.>
3.       The part of the HOB power filter that is in the water (I don’t know the technical name), is 6-8” from the bottom of the aquarium. Does this need to be extended farther down to the bottom of the aquarium, or id it fine there (I don’t know If there is current on the bottom of the tank)?
<It should be adequate as-is, though hang-on-the-back filters aren't the best filter design in this regard. Small canister filters, internal or external, can be more easily positioned at different levels to add more water movement at the top or bottom.>
4.       Because there is a flake of fish food sitting, unmoving in the center of the tank it makes me think there is little water movement there. Do I need some kind of power head or submersible pump down there to create more water circulation? If so how much is enough, and how much is too much?
<By all means add a small internal canister filter if you want, perhaps stuffed with ceramic noodles. Will do no harm, and may do some good. But if your fish seem happy, don't be too worried. Stressed (suffocating) fish will be lethargic, breathing heavily, coming up to the surface to gulp air.>
5.       Is my HOB filter which sits on one side of the tank enough to circulate the entire contents of the aquarium? I was considering purchasing another 200 GPH filter and placing it on the other back corner of the aquarium, and putting BOTH filters at about ½ power. In my mind that would eliminate the excessive “down” current, circulate water from multiple areas of the tank at once, and not cut down on the overall water cycling capability. Is that a dumb idea?
<Not a dumb idea at all. Indeed, could work well. But as I say, using a second filter design might be better.>
6.       A HOB filter seems to deposit the water back into the aquarium right by the water inlet (Again, I don’t know the technical name for this thing). Am I just re-filtering the same water over and over again?
<Shouldn't be, no.>
7.       Watching YouTube videos of people’s aquariums it seems some people with the HOB filters have then cranked  way up (Lots of water movement), and others seem to have them cranked way down (Little water movement). I have also seen “MODS” of people redirecting the flow (using a plastic cup so water enters the aquarium away from the water inlet to answer question #6 above), or putting a sponge in the exit path of the filter (to lower the turbulence or “Downward” current). If any of this necessary, or recommended?
<Depends on the fish. Discus dislike high water current, but need good water turnover rates because they're sensitive to ammonia and nitrite. On the other hand, Clown Loaches need masses of water current. So these two species will do best in tanks with filters "tweaked" to their needs.>
8.       Any other advice anyone had would be welcome!
I know “Different fish have different requirements”. There are some of the things I am considering putting in the tank (eventually… once cycling has completed, and I am confident about my other issues) Hammers Cobalt Blue Lobster (Procambarus clarkii) , Freshwater Clam (Corbicula sp.),
<Total and utter waste of time. WILL die, and WILL pollute the aquarium. Unless of course you'll be using marine aquarium filter feeder food, and squirting said food into clam 2-3 times per day, and somehow dealing with the excess nitrate that will be produced by uneaten food.>
Singapore Flower Shrimp (Atyopsis moluccensis),
<Demanding; will be killed by the Crayfish.>
GloFish® (Danio rerio) (assorted 6 pack),
<Danios can be nippy, especially towards fancy Goldfish.>
Cobra Guppy (Green or blue), Panda Oranda Goldfish (Carassius auratus), Hi Fin Lyretail Swordtail (Xiphophorus helleri), Harlequin Rasbora (Rasbora heteromorpha), Black Veil Angel (Pterophyllum sp.),
<Mix of hard water and soft water specious here… what's your pH and hardness?>
Albino Aeneus Cory Cat (Corydoras aeneus)… The list may change, and I don’t think I would get ALL of those species, that’s just to give an idea of what kind of fish I am considering.
Thank you!!!
<Do read. Cheers, Neale.>

stagnant water ? FW circ. f'   1/2/12
Hi WetWeb,
Hope you all had a great Christmas and a fishy New Year's :)
<Thanks!>
I have a long tall narrow 50 gallon tank which is not ideal but oh well.
<What, precisely, are the dimensions? Even small fish will be affected by the lack of surface area at the top (for oxygenation) and the bottom (for territory). Lack of width reduces effective swimming space, since things like Danios swim horizontally, not vertically. A standard 55 gallon tank in the US measures 48 by 20 by 13 inches, and actually holds a bit under 55 US gallons (and only 46 Imperial/British gallons). So you have a surface area of about 48 x 20 inches, or about 960 square inches. An old rule of thumb says you should allow 10 square inches for each "inch" of small fish (Neons, Guppies, that sort of thing), so a 55 gallon tank would hold something like 96 inches of fish, or about 96/1.5 = 64 fish like Neons that measure 1.5 inches in length. You can use this calculation to work out how many "inches" of fish your tank will hold, with the understanding that it holds for small fish and ignores the necessity for swimming space and territories, both of which need to be considered as well.>
The current plan is to set it up as a home for a few groups of very small fish. One end of the tank is half-round, at the other I am creating an overhanging river bank of potting clay mixed with vermiculite for weight reasons. Roots and branches sticking out, the water only reaching 2/3 or 3/4 of the tank height, ground-based plants on the overhang and plenty of floating plants, water circulation from end to end. For others interested in trying this, I wasn't confident in my potting skills so I first made a mockup in papier-mache laid over lumps of crumpled newspaper. The papier-mache turned out surprisingly well, since the medium naturally creates a sort of water-worn shape. It's been a fun project, as the papier-mache takes on a life of its own. I think the end result looks better than if I'd tried to control the shape more exactly.
<Cool. I have seen this sort of approach using Styrofoam and epoxy resin, for example:
http://www.sydneycichlid.com/fishtank-background.htm
>
Anyway, once the clay is fired and goes into the tank, there will be water trapped behind it. Do you think that will be a problem ?
<Potentially, yes. Anywhere water gets trapped can promote anaerobic decay.
That's not necessarily a bad thing -- live rock in marine aquaria works precisely because it promotes anaerobic decay -- but you do need to understand the risks and act accordingly.>
I could try to seal it with silicone and backfill with vermiculite or something lightweight, or could let the water leak around the edges and backfill with a wet soil/sand combination and hope that beneficial little organisms would grow in there, or could make it more open to the water (some caves and openings maybe ?) and place a small filter/pump behind to circulate the water back into the open area of the tank.
<Any of these sounds viable.>
Or I could just ignore the lack of circulation behind the sculptured area as the problem is mostly in my head :) What would you suggest ? I'm using a dirt-sand combination as a substrate in another tank and am very pleased with it*, but not sure about this tall an area that's kind of isolated from the main tank water. Malaysian trumpet snails may not care though ?
<They're not too fussy, but if there isn't enough oxygen they will climb to the top of the water.>
The volume is not that huge, maybe two or three gallons but over a foot deep.
* 8 gallon tank with Kuhli loaches ... the bottom is a 50-50 mixture of dirt and sand about a half inch deep, covered with round mixed-size river stones. Most aquarium sites recommend against large gravel or stones but boy, Kuhli loaches absolutely LOVE it. They dive in and out and through the rocks like it was Kuhli loach heaven. They also have an area of sand but just go there to bother the shrimp, then they rush back to their rocks.
Definitely a recommended experiment, if you haven't tried that. Looks really funny to see their front half buried in the rocks while the rear half sticks straight up thrashing the water, trying to jam themselves a quarter inch deeper after that little snack they desperately want. Kuhli loaches are insane :)
<I bet.>
Just came across this on another site and no I'm not spamming for them (http://www.skepticalaquarist.com/hyphessobrycon-innesi) and thought you might enjoy it :
"Paracheirodon innesi (Neon Tetra). In 1936 visitors to the Shedd Aquarium in Chicago lined up to view exotic Neon Tetras for the first time. They had been named by Dr Myers that year for W.T. Innes, and I'm just about the last to have given up the cherished old name of Hyphessobrycon innesi. The fish had been collected in the Amazon and shipped to Germany. Then they were flown back across the Atlantic in the dirigible airship 'Hindenburg'
... For years, while Neon Tetras were being flown out of Leticia, the exact locality from which they were being collected was kept tightly controlled as a 'trade secret;' it was even withheld from the scientists who formally described them. The location wasn't revealed until about 1960."
Kind of a trip :)
<Yes, a great story, and not unknown if you read the older aquarium books.>
Happy New Year to all of you and thanks again for your efforts on our behalf !
Jon B
<Glad to help. Cheers, Neale.>
Re: stagnant water ?  -- 1/3/12

Neale :
<Jon,>
Thank you for the quick reply. I'm actually encouraged by your estimate of the fish-carrying capacity of this size tank (55 gallons, 48" long and tall.) I'd planned to put about 2/3 that many tiny fish (plus a bunch of shrimp and some micro-spider crabs if I can find any) in there :)
<Fantastic idea, though all but the smallest fish will eat the crabs. But big tanks stocked with dozens if not hundreds of tiny fish can look amazing. If you have plants at all levels, but especially floating plants (the Micro Crabs basically live on floating plants and don't want to go anywhere else) then you can have something teeming with life, just like a reef tank, but at a fraction of the cost. I have a tank like that I call a "freshwater reef tank" because everywhere you look there's a baby shrimp or snail.>
I was thinking three groups - a flight of blackwinged hatchet fish for the top,
<Carnegiella marthae; nice fish, timid, could well eat the crabs, but worth a shot.>
a pack of marauding false tetra
<No idea what these are!>
(for tiny fish, they behave straight out of Clockwork Orange) for the middle, and a group of Kuhli loaches for bottom cleaners. They should each have their own sphere of influence and coexist well, would you think ?
<Yes, I agree.>
cf tiny fish, I know you don't like very small tanks for starters but there is another side to that story ... Kind of like getting thrown in at the deep end to learn to swim, an 8 gallon tank will teach you quickly or punish you harshly :) Mine taught me Restraint and appreciation for miniature life forms. Even more, for the interactions between various tiny life forms. You might consider that in certain cases (stubborn owners who need harsh lessons ?) very small tanks could be not such a bad idea '¦
<Quite so. I have two 8-gallon tanks and they're both fun. But the problem for beginners is the tendency to overstock. Angelfish in 8 gallon tanks are not a good choice'¦>
About backfilling behind the false riverbank, I'm intrigued by the concept of a modified deep sand bed. There was a surge of interest in it about a year ago here, then not much since. Did it turn out to be a bad idea or just not worth the effort when changing water accomplishes much of the same thing ?
<Oh my, it can/does work well. Do read:
http://www.wetwebmedia.com/ca/volume_7/volume_7_1/dsb.html
http://www.wetwebmedia.com/fwsubwebindex/FWDSBF.htm
With tiny fish, it works really well because they leave the sand alone, so the anoxic layer at the bottom isn't disturbed. Plants keep the substrate safe through their roots, and the whole thing becomes a very effective nitrate remover.>
Last question, water changes. At what point do they become counter-productive ?
<Not sure they ever do, provided water temperature and water chemistry stay constant. Think about a fish in a river -- it's constantly swimming in "new" water.>
Sometimes if I measure the water going in and the water coming out, the out water is better than the in water. API test kit but still, it's the same reagents at the same time for both samples. I've seen the ammonia in the tank actually lower than the ammonia in the 24 hour aged tap water with binding agent. Nitrates as well. Not *much* lower but enough to make me wonder if I shouldn't be drinking out of the fish tank instead of the tap '¦
<In a well-run, lightly-stocked aquarium, yes, "old" water can be rather good quality. But there's stuff we don't measure, like organic acids and phosphate, that can cause problems with pH and algae. So generally, regular water changes are important, provided water chemistry and temperature don't change wildly each time you do a water change.>
thanks again for your help
jb
<Glad to help. Cheers, Neale.>

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