Habitat Creation?

[IrvineHimself]

As I mention in this thread, by replacing my sponge filter and heater with something like the "Oase FiltoSmart Thermo 200" I can get between 5% and 10% more habitat. I intend to plant the area currently occupied by the sponge filter and its camouflage with an easily manicured, low lying aquatic grass. Which leaves a strip 5cm wide by 40cm long where the heater used to reside:

As you can see in the photo, the strip of new habitat lies in a natural channel formed by a long piece of driftwood used to camouflage the heater and the glass wall of the Aquarium. The para-cord knots and SS mesh are seeded with Christmas Moss, while the driftwood is planted with Pygmy Bucephalandra.

When @FrozenShivers mentioned the high flow rate of cannister filters compared to my existing sponge filter, I got me thinking: Way back in January, when I first started to plan out a possible Aquarium, I was drawn to odd-ball fish. In particular Kuhli and Hillstream Loaches. Unfortunately, at the time, because of their preferred habitats, the two species seemed mutually exclusive. As a result, I now have a playful group of 4 Kuhlis who have made a sandy bed around the air-stone in the opposite corner of the tank.

So, my question is: If I remove the air-stones and stem plants currently occupying the channel, and use my siphon to excavate a deep trench in the sandy substrate which I can fill it up with pebbles. Then, using for example, a duck nozzle or similar positioned close to the gravel bed, I could angle the outflow along the channel and create a preferred habitat for a couple of Hillstream Loaches. Obviously, they would not be restricted to this channel and they could spend as much time as they liked in the rest of the tank, but it would give them a little bit of habitat specially tailored for them.

In the view of more experienced Aquarists, does this sound like a workable plan?

As an aside, if it is workable, the small river I create would actually solve another of my problems. Namely: circulation through the network of caves which run the length of my tank. As originally designed, the heater was supposed to provide a convection current, but with the recent heatwaves, the heater has never come on-line. With a small river running past the back entry to the caves, the Bernoulli effect [think 'No Spill' water change] would create the desired circulation.

 

[IrvineHimself]

Okay, I have been re-reading species profiles on Hillstream Loaches and giving the mechanics more thought.

With reference to this species profile, the problem with keeping a Hillstream Loach in a small tank is that, without adequate space to direct the current, the flow requirements are disruptive to the other habitats. So, what are the flow requirements?

Quoting from the linked profile:

1. "Hillstream loaches need very oxygen-rich water in order to thrive. The complete lack of water flow can actually even kill them in some situations. "
2. "The reticulated hillstream loach is a huge fan of fast-moving water and is normally found in rivers and streams throughout Asia that have strong currents."

While I might not be able to create a current at 'power-head' levels, there are a number of things I could do to recreate the described environment. Namely, a line of air-stones buried in the gravel bed would not only increase the oxygen levels of the water, but would also:

1. Create a line of low pressure along the 'river-bed', which, since it would be the path of least resistance, the filter outflow would naturally follow.
2. Create random, turbulent currents in addition to those provided by the filter outflow.

For a first look at the mechanics: Assuming a tank where the water is completely static, the water pressure at the outflow is calculated by 'density*gravity*depth + standard atmosphere' = 3 + 101 = 104 kPa. Or, 3% higher than the filter expects. Since only the most highly specced equipment has tolerances as close as 3%, I would think the filter could operate at that depth, albeit with slightly reduced flow rate.

So, assuming roughly 80% efficiency, an expected flow rate of 600 litres per hour would not be unreasonable. This works out at a flow rate of 167 ml/s

As an experiment, I took a 5ml syringe and directed it along the substrate:

1. Emptying the syringe in about 2s [2 or 3 ml/s], the sand was disturbed over 10 or 11 cm from the experimental outflow.
2. The diameter of the syringe outflow is about 2mm. (My eyesight is really bad, so I may I may be slightly off with my measurements)

Using this handy on-line calculator, the velocity of the water exiting the syringe is about 95cm/s, while with just a plain elbow joint outflow, and the suggested flow rate of 600l/h, the velocity of water at the filter outflow would be around 126 cm/s or 5 km/h, (about walking speed)

The question is: Would the measures I have outlined be enough to keep Hillstream Loach happy and healthy, or rather, would it be more likely to burn out the filter?

Irvine

Note: Referring to this, second, species profile: "We recommend getting just one or a group of three or more. If you get two, the stronger one may bully the weaker one over food or territory". In view of this, I would only be looking to create habitat for a single Hillstream Loach.

 

[dw1305]

Hi all,

The question is: Would the measures I have outlined be enough to keep Hillstream Loach happy and healthy, or rather, would it be more likely to burn out the filter?

Others may disagree, but I don't think it is really a suitable long term set-up for Hill-stream Loaches.

If I was going to keep them (and <"I have thought"> about <"Sewellia lineolata">), I would only do it in a dedicated setup - <"Hillstream Loaches - The Specialists at Life In The Fast Lane — Loaches Online">.

I actually now have a <"different approach to fish keeping"> (and <"gardening">) in that <"I find fish that naturally like the conditions I can provide">, rather than trying to <"alter what I have to suit a certain fish">.

I use an even less precise method for soft water fish, I cut my rain-water with tap-water (about 17dKH) to give about 70ppm TDS (100 - 120 microS). I don't bother measuring anything else, and I use the Duckweed Index to feed the plants when they really need it.

This method still leaves the water too hard to breed "Blackwater" fish like Dicrossus filamentosus, but it is fine for their maintenance.

cheers Darrel

 

[IrvineHimself]

Others may disagree, but I don't think it is really a suitable long term set-up for Hill-stream Loaches.

Yeah, I thought as much. I realised way back in January that keeping Kuhli and Hillstream loaches in the same small tank wasn't going to work. It was just when the subject of 'flow rate' came up that I got to thinking: "Mmm... Hillstream Loaches?"

I think I will still aqua-scape the space liberated from the heater as a small river with 3 or 4 cm pebbles for a gravel bed. If nothing else, my rock-gobies [of which I would like a few more] would like the new habitat. Also, if I sculpt a riser at the end opposite the outflow, I should have space for an exotic epiphyte. In fact, I could sculpt the area around the outflow as well and have space for a second epiphyte.

Edit: I should add that I really need the suction it will create at the mouth of the cave network.